In Situ Tunneling Microscopy for Platinum Surfaces in Aqueous Solutions

Article abstract of DOI:10.1021/j100334a045

An in situ scanning tunneling microscope was applied for platinum (Pt) surfaces in aqueous solutions.Pt particles, electrodeposited on a highly ordered pyrolytic graphite, were investigated in detail.It was revealed that the shape of the Pt particle was not a smooth semisphere.There were many iregular dislocations such as steps and boundaries.Pt whiskers were also observed.The in situ measurement of Pt electrodes was carried out before and after an electrochemical activation in an aqueous solution of sulfuric acid.Large changes in the surface structure were induced by an electrochemical activation procedure.Very regular parallel-terrace structures appeared, suggesting that the migration of adatoms of Pt produced by the oxidation and reduction cycles should occur toward a particular crystallographic direction.Semispherical domains were oserved at different portions of the surface.It was concluded that different morphologies appearing at different points were probably caused by the orientation of each small single crystal composed in the sample.