A kinetic model for redox replacement of UPD layers

The redox replacement at open-circuit potential (OCP) of the underpotentially deposited (UPD) metal layer in the presence of oxygen and/or more noble metal ions is discussed and an analytical model describing this process is proposed. The model establishes a functional relationship between time and potential during the replacement of the UPD layer featuring either Langmuir- or Frumkin-type adsorption behavior. A model validation is performed by fitting experimental OCP transients for oxidative Pb stripping from Cu(111) and Ag(111) substrates. The excellent agreement between theory and experiment enables quantitative prediction and control of the replacement reaction kinetics in a wide variety of systems. (c) 2007 The Electrochemical Society.