Water dissociation at MgO sub-monolayers on silver: a periodic model study

Area of Science:

• Surface science
• Computational chemistry
• Materials science

Background:

• Water interaction with metal oxide surfaces is crucial for catalysis and environmental processes.
• Understanding dissociation mechanisms on oxide thin films informs material design.

Purpose of the Study:

• To investigate water dissociation at the borders of sub-monolayer Magnesium Oxide (MgO) films on a Silver (Ag)(100) substrate.
• To compare reaction energetics for polar and non-polar MgO film borders.
• To validate theoretical calculations against experimental data.

Main Methods:

• Hybrid-exchange Density Functional Theory (DFT) Hamiltonian.
• Periodic slab model for surface simulation.
• Calculation of O-1s core level shifts.
• Calculation of O-H vibrational frequencies.

Main Results:

• Water dissociation was simulated at MgO film borders on Ag(100).
• Higher reaction energy was found for non-polar borders compared to polar ones.
• Calculated O-1s core level shifts and O-H vibrational frequencies align with experimental X-ray Photoelectron Spectroscopy (XPS) and High-Resolution Electron Energy Loss Spectroscopy (HREELS) data.

Conclusions:

• The study provides insights into water dissociation mechanisms on MgO thin films.
• Theoretical findings support experimental observations, validating the computational approach.
• The results contribute to understanding surface chemistry at oxide-metal interfaces.