CeO 2 thin film electrode with a built-in electrochemically resetable oxidant for potentiometric stripping analysis

Abstract

In this work a sol-gel derived CeO 2 thin film, deposited on a glass substrate, was investigated for its potential use as a working electrode in potentiometric stripping analysis (PSA). The work was focused primarily on examination of the PSA performance of a CeO 2 film electrode, where Ce(IV) can be exploited as a built-in chemical oxidant that can be electrochemically regenerated by the application of an appropriate anodic potential. The CeO 2 thin film electrode exhibits a well-defined PSA response to Cu 2+ in a solution, chosen as a convenient test cation. Its electrochemical behaviour in the presence of supporting electrolyte LiCl and Cu 2+ was investigated by cyclic voltammetry. It was found that a very simple but crucial electrochemical pretreatment and conditioning of the CeO 2 electrode was necessary for its good PSA performance. The parameters influencing the PSA signal, such as deposition potential and time, were studied. The linearity of the PSA signal versus Cu 2+ concentration and its repeatability were also examined and found satisfactory. The suitability of the CeO 2 thin film as a mercury free PSA electrode, with no need of an external oxidant, is discussed.