Re-visiting the O/Cu(111) system--when metastable surface oxides could become an issue!

Area of Science:

• Surface Science
• Catalysis
• Materials Science

Background:

• Copper-based catalysts are vital for methanol synthesis, partial oxidation, and water-gas shift reactions.
• Surface oxidation significantly impacts the functionality of these catalytic systems.
• The "8"-structure oxide phase on Cu(111) has been experimentally observed.

Purpose of the Study:

• To assess the stability and population of the "8"-structure oxide phase on the Cu(111) surface.
• To understand the role of this oxide phase in copper-based catalytic processes.

Main Methods:

• Density-functional theory (DFT) calculations.
• Ab initio atomistic thermodynamics.
• Boltzmann statistical mechanics.

Main Results:

• The "8"-structure is confirmed as a metastable oxide phase on Cu(111).
• Its population is competitive with established "29" and "44" oxide film structures.
• The atomic configuration of the "8"-structure resembles Cu2O(110), suggesting potential reactivity.

Conclusions:

• The "8"-structure is a significant, metastable phase on Cu(111) surfaces.
• Its similarity to the active Cu2O(110) facet implies it could be a reactive phase in catalysis.
• This research provides critical insights into the surface chemistry of copper catalysts.