Gold adatoms modulate sulfur adsorption on gold.

Area of Science:

• Surface Science
• Computational Chemistry
• Materials Science

Background:

• Sulfur adsorption on Au(111) at high coverage presents complex structural assignments.
• Existing models include monomeric S, S2, mixed species, and gold sulfide.
• Understanding these structures is crucial for catalysis and materials development.

Purpose of the Study:

• To elucidate the atomic structure of sulfur adsorbed on Au(111) at high coverage.
• To resolve the ambiguity in structural assignments of sulfur species.
• To provide a unified model for gold-sulfur surface chemistry.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Simulations focused on high-coverage sulfur adsorption on the Au(111) surface.
• Analysis of structural stability and electronic properties.

Main Results:

• Monomeric sulfur reorganizes into S2 species at high coverage.
• These S2 species are stabilized by gold adatoms, forming gold disulfide complexes (Au-(S2)4).
• This model explains experimental observations from STM and XPS, and provides a pathway to gold sulfide.

Conclusions:

• The gold disulfide complex model offers a unified explanation for high-coverage sulfur adsorption on Au(111).
• This resolves previous ambiguities regarding sulfur species and surface structures.
• The findings advance the understanding of gold-sulfur surface chemistry relevant to thiols and sulfur species.