The irreversible characteristic analysis of thiourea on copper electrodes in aqueous 0.5 mol/L sulphuric acid

By Zhao, Jie; Li, Ning; Gao, Shan & Cui, Guofeng
Published in Electrochemistry Communications NULL 2007

Abstract

The reaction behaviors of various concentrations thiourea (TU) on copper electrode in 0.5 mol/L H2SO4 solution were investigated by electrochemical impedance spectroscopy (EIS) and single crystallogram. The loop at low frequency shifts negatively with the concentration of TU increasing to 0.25 mol/L in the research. It reveals the adsorption of TU converts the acidic corrosion of copper electrode to the final irreversible complexation of copper and TU. Furthermore, the dependence of irreversiblility on Cu(I)–TU complex surface coverage (θ) was discussed by an EIS mathematical model. The three-dimensional supermolecular network structure of [Cu2(NH2CSNH2)6]SO4 · H2O enhances the stability of the complex, and leads to the final irreversibility of whole reaction.

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