Following Adsorption Kinetics at Electrolyte/Metal Interfaces through Crystal Truncation Scattering: Sulfur on Au(111)

Abstract

Combining electrochemical methods, in situ scanning tunneling microscopy, and surface x-ray diffraction allowed study of the structure and kinetics of S/Au(111) electrodes in aqueous electrolytes under potential control. Integrated intensities of a particular crystal truncation rod at anti-Bragg conditions were used to trace the sulfur adsorption and desorption as a function of electrode potential in real time. The S desorption is a first order process and the adsorption follows a Langmuir isotherm. A weakly bound S layer is found on the surface before charge transfer, and then specific adsorption occurs.

A scanning tunneling microscopy investigation of the phases formed by the sulfur adsorption on Au(100) from an alkaline solution of 1,4-piperazine(bis)-dithiocarbamate of potassium

“…Average periodicities of 0.89 (±0.03) nm × 0.89 (±0.03) nm, average size of 0.53 (±0.03) nm × 0.52 (±0.04) nm and average distance between atoms of 0.27 (±0.02) nm × 0.26 (±0.03) nm were measured for the octomers. These data were in accordance with reported measurements [24][25][26]28,32,33], further confirming the efficient deposition of sulfur through the use of piperazine-dithiocarbamate of potassium in alkaline solution. The average periodicity of the other phase was 0.46 (±0.04) nm × 0.44 (±0.04) nm, corresponding to a √ 2 × √ 2 structure.…”

“…A large diversity in molecular arrangements at intermediate and high sulfur coverages on Au(111) has been reported using STM. Some of these are the octomer formed by a quasi-square structure with eight atoms [33][34][35] and distortions of this phase, where certain sulfur atoms have slightly changed positions to generate different arrangements on the Au(111) surface [24,25,35,36]. Other interesting structure which forms a zig-zag pattern has been also observed [25].…”

“…Some authors have proposed the use of S 2 and SO 2 from the gas phase [29][30][31] and from electrochemical oxidation of gold surfaces in the presence of Na 2 S [32,33] in order to study sulfur/gold interactions. They have reported that sulfur is initially chemisorbed on Au(111) at the step edges.…”

Reaction of Au(111) with Sulfur and Oxygen: Scanning Tunneling Microscopic Study

“…In particular, morphological changes during formation of self-assembled monolayers (SAMs) that limit edge definition in soft lithography are not well understood. Many models have been proposed based on the assumption that the Au atoms are unperturbed during sulfur adsorption [23,27,28]. However, as mentioned earlier, it may be important to consider that Au atoms released from Au surface are possibly involved in the interaction with sulfur atoms.…”

Adsorption phenomena of cubane-type tetranuclear Ni(II) complexes with neutral, thioether-functionalized ligands on Au(111)

“…7a is long-range ordered and covers large areas of the sample surface. STM data do not allow an unambiguous chemical identification of the six alike looking building blocks within the surface unit cell, but by comparison with literature data [34] and our XPS data, we can safely conclude that we observe atomic sulfur on Au.…”