A first-principles study of bulk oxide formation on Pd(100)

Area of Science:

• Materials Science
• Surface Chemistry
• Catalysis

Background:

• Palladium's catalytic activity is sensitive to its oxidation state.
• Oxidation and decomposition of palladium oxides occur under operational conditions.
• Understanding palladium oxide film formation is crucial for catalysis.

Purpose of the Study:

• Investigate the transition from surface to bulk palladium oxide on Pd(100).
• Determine the stable oxide film orientation and growth mode.
• Analyze the impact of oxide thickness on electronic and chemical properties.

Main Methods:

• First-principles calculations based on density functional theory (DFT).
• Modeling of palladium oxide film growth on Pd(100).
• Thermodynamic and electronic property analysis of oxide films.

Main Results:

• The most stable oxide orientation is PdO(101)@Pd(100) across all film thicknesses.
• Monolayer oxide exhibits distinct electronic, chemical, and thermodynamic properties compared to thicker films.
• Carbon monoxide adsorption is significantly stronger on thicker oxides, impacting catalytic activity.
• DFT-based modeling predicts a Stranski-Krastanov growth mode with a critical thickness of 1 monolayer (ML).

Conclusions:

• The study provides a theoretical framework for interpreting experimental palladium oxide growth.
• Findings highlight the importance of oxide thickness and orientation in determining catalytic performance.
• The unique properties of the palladium oxide monolayer are identified as a key factor in surface reactions.