Electrochemical Codeposition and Spectroscopic Characterization of Cu-Tl Oxide Films Prepared in Aqueous Basic Solutions

b Centro di servizi Interdipartimentali di Microscopia, Universitadegli Studi della Basilicata, 85100 Potenza, Italy Composite thallium-copper ~Cu-Tl! oxide films supported on glassy carbon were prepared by electrodeposition from citrate alkaline solutions. The resulting Cu-Tl deposits were characterized by cyclic voltammetry, X-ray photoelectron spectroscopy ~XPS!, and scanning electron microscopy. Upon deposition the electrochemical activity of copper was evaluated in NaOH solutions as a function of thallium and citrate concentrations along with sweep potential limits. The electrochemical activity of copper appears to be enhanced by the codeposition of thallium oxide species. The high activity of copper, in the presence of thallium oxides, may be considered as mainly due to a marked augment of the active surface area of the electrode material. The XPS depth profiling reveals an almost homogeneous distribution of the Cu/Tl atomic ratio within the deposited films, with a slight enrichment of copper oxide species on the surface electrode relative to bulk; an average chemical composition of Cu45Tl55 was established.