The charge transport process at nickel hydroxide gold-modified electrodes

B. CARAM; R. TUCCERI

Beijin

Congreso; World Congress on Engineering and Technology (CET2012); 2012

Abstract—The aim of the present work was study how the charge-transport processes of a nickel hydroxide film electrochemically synthesized is modified when the electrode is stored without use for long time. This study was carried out in the context of the rotating disc electrode voltammetry when the modified electrode contacts an electroactive solution and a mediation reaction occurs at the Au-Ni(OH)2|electrolyte interface. Variations of anodic limiting currents with the electrode rotation rate, for both nondeactivated and deactivated films in the presence of the electroactive solute deferasirox allowed one obtaining a charge transport rate across a nickel hydroxide film, which decreases with the increase of the storage time. However, the magnitude of the deactivation also depends on the nickel hydroxide surface loading (or thickness). In this regard, thick films are less deteriorated than thin ones at a fixed storage time. Deactivated films do not recover the initial response corresponding to an immediately prepared film even after prolonged potential cycling. As nickel hydroxide is often employed as electroactive material in the determination of different organic and biologically important products, a freshly prepared film should be used in each one of these measures. Keywords-nickel hydroxide gold-modified electrodes; mediation reaction; charge transport process; nickel hydroxide deactivation