Does Pb Underpotential Deposition Rearrange Surface-near Atoms in AgAu Films and Nanoparticles?
Dean-Robin Nettler, Jan Clausmeyer, Alan Savan, Paolo Cignoni, Christian Rurainsky, Ralf Drautz, Alfred Ludwig, Kristina Tschulik
Bimetallic surfaces consisting of Ag and Au in various ratios, as sputtered thin films as well as wet-chemically synthesised nanoparticles were modified by underpotential deposition of Pb (Pb-UPD). On the basis of characteristic voltametric peaks along with supporting DFT calculations we conclude that depositing Pb on the Ag-rich surfaces induces a swap of Ag atoms with underlying Au atoms to form a Au-rich layer in the presence of the Pb monolayer. Our experiments showed that Pb-UPD is a powerful tool not only to probe the surface composition and structure but to change the arrangement of surface atoms in binary alloys.