L.M. Gassa,a A.M. Castro Luna,a R.M. Torres Sánchez, b J.O. Zerbinoa,*
aInstituto de Investigaciones Fisicoquimicas Teóricas y Aplicadas (INIFTA), UNLP, Sucursal 4, C.C. 16, (1900) La Plata, Argentina.
bCentro de Tecnología de R. Minerales y Cerámica. C.C. 49, (1987) M. B. Gonnet, Argentina.
Received 31 December 2002; accepted in revised form 26 May 2003
Abstract
The semiconducting properties of anodic passive films formed on polycrystalline copper in aqueous borax solutions, pH 9.2, are studied using electrochemical impedance spectroscopy (EIS) and voltammetry. The semiconducting nature of the cuprous passive layer is analysed in the potential region near de rest potential as a function of the electrode potential and the presence of CO dissolved in the electrolyte. The oxide formation is explained as a sequence of Cu2O growth, cation adsorption, Cu(II), and dissolution steps similarly to previous reported investigationsfor the metal in CO free solutions. The different growth conditions change the defect or excess of cations accumulated in the outer side of the cuprous layer/electrolyte interface leading to different semiconducting properties.
]]>Keywords: copper oxide, carbon monoxide, EIS, isoelectric point, semiconducting properties
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*Corresponding author. E-mail address: jzerbino@inifta.unlp.edu.ar
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