Role of Gold Adatoms in the Adsorption of Sulfide Species on the Gold(001)-hex Surface

CARRO, PILAR; SALVAREZZA, ROBERTO C.; CARRO, PILAR; SALVAREZZA, ROBERTO C.; VERICAT, CAROLINA; GRUMELLI, DORIS; VERICAT, CAROLINA; GRUMELLI, DORIS; MAZA, FLAVIA LOBO; KERN, KLAUS; MAZA, FLAVIA LOBO; KERN, KLAUS

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Año: 2018 vol. 122 p. 2207 - 2214

1932-7447

: We have studied the adsorption of reduced sulfur species on the Au(001)-hex surface from diluted ethanolic sulfide solutions by STM, XPS, electrochemicaltechniques, and DFT calculations. Our results reveal the absence of S multilayers becauseall S species are bonded to Au surface atoms. Monomeric S adsorbs at hollow sites forminga (2 × 2) lattice, while S2 species either capture the gold adatoms (Auad) that result fromthe hex lifting or remove Auad from the substrate forming well-ordered S8-like structures.These are formed by four S2 species coordinated by a central Auad, with AuSS interatomicdistances closely resembling those of a metal disulfide. Our results explain not only thepredominant surface structures on the gold surface but also topographic features, like Auadislands and Au vacancy islands, and also the chemical nature of adsorbed species from XPSS 2p spectra. In contrast to the S heads of small aromatic thiols, which exhibit a low affinityfor Auad, strongly reactive sulfide species react with the metal adatoms leading to wellorderedcomplexes.