No abstract

I n situ scanning tunneling microscopy was applied to single-crystal platinum (111) surfaces both before and after electrochemical potential cycling in an aqueous sulfuric acid solution. Steps observed on a Pt(111) facet were usually located on nearly parallel straight lines or on the directions forming an angle of close to 60°, as expected for a surface with threefold symmetry. The height of each step was in accord with the monatomic step height of 0.238 nm on the Pt(111) surface. Randomly oriented islands a few atoms in height were clearly observed on the terraces after five potential cyclings. It was suggested that Pt adatoms produced by the reduction of the oxide are coagulated on the terraces.

No abstract

An in situ scanning tunnelling microscope was applied, for the first time, to a single-crystal platinum { 1 1 l} surface both before and after electrochemical potential cycling in aqueous sulphuric acid solution. The single-crystal Pt{ 11 l} was annealed in a flame near 1100 "C for 1 min and then quickly brought into contact with pure water. It was not possible to see any particular structures on the fire-annealed single crystal. It is shown that the fire-annealing procedure can produce an almost completely atomically flat surface on a single crystal. The flat { 11 l} surface of the Pt crystal was roughened by the electrochemical potential cycling. Semi-spherical domains have predominantly been observed on the single crystal. These domains seem to be randomly distributed over the surface. The diameter and heigbt of the semi-spherical domains were in the ranges 20-30 and 5-10A, respectively.

A scanning tunneling microscope was constructed for in-situ electrochemical studies. The apparatus could provide atomic resolution of a highly oriented pyrolytic graphite (HOPG) surface in both air and aqueous solutions. The electrodeposition of platinum (Pt) on the surface of HOPG was investigated.