Potential dependent structure of single crystal gold interfaces in alkaline electrolyte: an in situ X-ray scattering study

Abstract

An X-ray scattering study of the structure of gold (001), (111), and (011) single crystals in 0.1M KOH electrolyte found that all three faces were reconstructed in the potential region where hydroxyl coverage was low. For the (001) and (111) surfaces, the reconstruction had a structure generally similar to the vacuum reconstruction (i.e. discommensurate distorted hexagonal and uniaxial compression, respectively). The (011) surface had a (1 × 3) "missing row" reconstruction, the same as found in neutral salt electrolytes, but different from the vacuum (1 × 2) reconstruction. The potentials at which the reconstruction formation and removal began were similar for all three faces. The kinetics of the reconstruction formation and removal were generally faster than in acidic electrolytes with non-adsorbing anions. The significant differences in the kinetics of transformation between the three faces were attributed to the markedly different density changes between the (1 × 1) and reconstructed structures and the consequent surface diffusion requirements. © 1994.