Anion replacement at Au(110)/electrolyte interfaces

Abstract

A characteristic reflection anisotropy spectrum (RAS) is observed from a Au(110) surface in a wide range of electrolytes and combinations of pH and applied potentials. It is suggested that this common RAS profile arises from an interaction between the potential applied to the Au(110) electrode and the dipole moments of oxidized species that locates the Fermi level at a common position with respect to the electronic band structure of Au. Rapid changes in this RAS profile are observed for Au(110)/H2SO4 as the potential is switched between 0.3 V and 0.6 V, a potential range in which the surface is not reconstructed and below the potential range of surface oxidation. The spectral changes are completed in less than 10 ms, are reversible and are attributed to the replacement of adsorbed anions by an oxygenated species.

Experimental and Computational Aspects of Electrochemical Reflection Anisotropy Spectroscopy: A Review

“…Contributions to the complex dieletric function arise both from the bulk and the surface. The slight differences between the spectra are due to different interband transitions from different Fermi level positions [80] . In general, the results in sulfuric acid (H 2 SO 4 ) agree with those of Mazine et al [84] .…”

“…The slight differences between the spectra are due to different interband transitions from different Fermi level positions. [80] In general, the results in sulfuric acid (H 2 SO 4 ) agree with those of Mazine et al [84] The blue curve was recorded under open-circuit potential and shows a characteristic RA spectrum of well-ordered unreconstructed (1 � 1) Au (110) in an acidic environment. [84] The spectra obtained under applied potentials exhibit similar features as the spectrum measured in H 2 SO 4 .…”

“…First applications of EC‐RAS were dedicated to the study of different gold single‐crystalline surfaces in aqueous electrolytes. These studies have outlined the relationship between surface charge and reconstruction by measuring RA spectra for interfaces between Au(110) and aqueous electrolytes while potentials were applied to Au(110) [79,80] . Yet, their investigation focused exclusively on experimental EC‐RAS and were corroborating previous findings evidenced by STM.…”

“…These studies have outlined the relationship between surface charge and reconstruction by measuring RA spectra for interfaces between Au(110) and aqueous electrolytes while potentials were applied to Au (110). [79,80] Yet, their investigation focused exclusively on experimental EC-RAS and were corroborating previous findings evidenced by STM. Similarly, Sheridan et al have combined experimental RAS with the modelling of the surface optical response -not full ab initio computational spectroscopy -to investigate the impact of surface phases transition and surface roughening of Au (110) in sulfuric acid under applied voltage on the electronic structure.…”