Electrochemical deposition of copper on stepped platinum surfaces in the [01(1)over-bar] zone vicinal to the (100) plane

The electrochemical deposition of copper on stepped platinum surfaces vicinal to the (100) plane in the [01 (1) over bar] zone was investigated in the underpotential deposition regime by cyclic voltammetry. The influence of the step density and different anionic species on the electrodeposition process has been studied. The deposition of copper on stepped surfaces is characterized by the presence of different voltarnmetric peaks. These peaks are assigned to adsorption of copper on surface sites of different geometry, based on the analysis of the charges and their comparison with the hard sphere model for the ideal surfaces. Moreover, the possibility of step decoration has been explored by using diluted copper solutions (10(-6) Cu2+). Under these conditions, the rate of deposition is very slow, limited by mass transport, and the deposition process can be followed by the continuous evolution of the cyclic voltammogram. It has been found that copper preferentially adsorbs on (100) terrace sites, instead of on (111) steps. A tentative explanation based on the different coordination of copper on both sites is proposed. (C) 2008 Elsevier B.V. All rights reserved.