STUDY OF THE ELECTROCHEMICAL-BEHAVIOR OF GOLD(111) VICINAL FACES SITUATED ON THE [01(1)OVER-BAR] ZONE IN AQUEOUS-SOLUTIONS

The atomic structure and electrochemical properties of three (111) vicinal orientations on the [011BAR] zone (Au(11,9,9), Au(433) and Au(755)) are studied. A combined low energy electron diffraction and Auger electron spectroscopy study shows that two stable structures can exist for the (11,9,9) and (433) orientations. The (1 X 1) structure is obtained without annealing and the faceted structure, with (111) and (755) facets, corresponds to an annealed surface. The electrochemical behaviour of the (1 x 1) and faceted structures is identical. Therefore monatomic (100) steps on a (111) terrace have a specific and autonomous electrochemical behaviour, which is identical with that of a (755) plane. These results show how monatomic steps can induce electrochemical perturbations on an imperfect surface of a (111) single-crystal electrode.