%0 Journal Article
%A Garcia, S. G.
%A Salinas, D. R.
%A Staikov, G.
%T Underpotential Deposition of Cd on Ag(111): An in situ STM study
%J Surface science
%V 576
%@ 0039-6028
%C Amsterdam
%I Elsevier
%M PreJuSER-38552
%P 9 - 18
%D 2005
%Z Record converted from VDB: 12.11.2012
%X The kinetics and mechanism of Cd underpotential deposition (UPD) and involved surface alloy formation processes the system Ag(1 1 1)/Cd2+,SO42- are studied by means of combined electrochemical measurements and in situ scanning tunneling microscopy (STM). The results show that the UPD process starts with a formation of an expanded (diluted) adlayer with a superlattice structure Ag(1 1 1)-(root3- x root19)R23.4degrees. In the underpotential range 50 mV < DeltaE < 80 mV this adlayer transforms to a condensed close packed Cd monolayer via a first order phase transition. At long polarization times the condensed monolayer undergoes structural changes involving place exchange processes between Cd atoms and surface Ag atoms. A formation of a second Cd monolayer and a significant Ag-Cd surface alloying take place at lower underpotentials (DeltaE < 50 mV). The kinetics of surface alloying are analyzed on the basis of a recently proposed diffusion model including a relatively fast initial formation of a very thin surface alloy film and a subsequent slow alloy growth controlled by solid state diffusion. The anodic dealloying results in an appearance of monatornically deep pits, which disappear quickly at relatively high underpotentials (DeltaE > 550 mV) indicating a high mobility of surface Ag atoms. (C) 2004 Elsevier B.V. All rights reserved.
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000226872600004
%R 10.1016/j.susc.2004.11.037
%U https://juser.fz-juelich.de/record/38552