An in situ STM study on Sb electrodeposition on Au(111): irreversible adsorption and reduction, underpotential deposition and mutual influences

We present an in situ STM study on submonolayer Sb electrodeposition on Au(1 1 1). Different approaches have been employed to study Sb irreversible adsorption, the redox behavior of the Sb(III) adspecies with and without the influence of UPD and vice versa. The oxygenous Sb(III) is adsorb on Au(1 1 1) surface at potentials between 0.2 and 0.55 V, which is very likely in the form of in-plane oriented SbO(+) layer conjugated with the sulfate. In the solutions containing only sulfuric acid, this anion bound film undergoes a subtle structural change after the completion of discharge from Sb(III) to Sb(O) state at similar to0 V In the Sb(III) containing solutions, the film type of structure of the adspecies is destroyed at the potential where Sb UPD takes place and more Sb can be incorporated, leading to structural transition to a worm-like network. Alloys at least involving two top layers of the surface are formed accompanying the structural transition. The Sb UPD without precedent with the irreversible adsorption proceeds by forming monoatomic high alloy islands of similar to10 mm in diameter. The apparent simple surface morphology provides evidence con that the channels within the complex worm-like network may well be a result of oxygen removal from the in-plane orientated SbO(+) layer and alloy formation as well. (C) 2003 Elsevier Science B.V. All rights reserved.