A model for the flux of the species generated during the electrodissolution of a copper–nickel alloy on Pt in acidic media

Abstract

This paper describes a new model to calculate the fluxes of the species generated during the electrodeposition of Cu–Ni alloys on Pt in acidic media. Measurements were carried out using linear sweep voltammetry and electrochemical quartz crystal microbalance (EQCM) techniques. The alloy electrodeposition was performed between +1.0 and −0.9 V versus SCE in a bath containing 0.04 M CuCl 2·2H 2O+0.04 M NiCl 2·6H 2O+0.32 M H 3BO 3+1 M NH 4Cl. Following this, a sweep in the positive direction (between −0.3 and +1.0 V) to dissolve the alloy was performed using a blank solution (1 M NH 4Cl+0.32 M H 3BO 3). The fluxes of the species versus the potential (Ni 2+ (desorption) and Cl − (adsorption on the top of Cu +)) generated during the alloy dissolution were calculated using the current and mass responses. In fact, it was observed that the electrodissolution obeys Faraday's law. The flux calculated (considering a transference of two electrons in the case of Ni and one electron in the case of Cu) multiplied by the Faraday constant and plotted against E ( i calculated) presents the same profile as the experimental results for the alloy dissolution.