Metal-water interface formation: Thermodynamics from ab initio molecular dynamics simulations

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Understanding metal-water interfaces is crucial for various scientific fields.
• Limited experimental and computational data hinder accurate thermodynamic property assessment.

Purpose of the Study:

• To compute thermodynamic quantities for metal-water interface formation.
• To investigate wettability and interfacial water properties.
• To provide benchmark data for computational methods.

Main Methods:

• Density functional theory based molecular dynamics.
• Two-phase entropy model.
• Calculations for FCC(111) surfaces (Pd, Pt, Au, Ag, Rh, PdAu).

Main Results:

• Metal-water interface formation is thermodynamically favorable.
• Most studied metal surfaces exhibit complete wettability (zero contact angle).
• Interfacial water shows higher entropy than bulk water, influenced by low-frequency modes and ordering.
• Entropic contributions significantly impact formation free energy (up to ~25%).
• Water adsorption energy is a partial descriptor; interface formation is driven by energetic and entropic interplay.

Conclusions:

• Metal-water interfaces are favorable and wettable, driven by energetic and entropic factors.
• Interfacial water entropy is higher due to specific structural and dynamic properties.
• Results offer fundamental insights and benchmark data for theoretical and computational studies.