Formation of copper adatom layers on polycrystalline platinum: Adsorption or two-dimensional growth?

Formation of adatom layers of copper on polycrystalline platinum in 0.5 M H 2SO4 + 0.01 M CuSO4 and 0.5 M HClO4 + 0.01 M Cu(ClO4)(2) is studied using c hronoamperometry and cyclic voltammetry. At E > 0.35 V, adsorption occurs o n the surface sites with a high energy of the Cu-Pt bond. Near the equilibr ium copper potential (0.25-0.35 V), a two-dimensional growth of the Cu(1 x 1) phase is observed. This process is accompanied by the restructuring of a dsorption lattices which consist of copper adatoms and co-adsorbed anions. At cathodic overvoltages, a three-dimensional copper nucleation starts afte r a monolayer of adatoms of Cu(1 x 1) is formed, which means that the Stran sky-Krastanov mechanism is realized.