Investigation of glucose electro-oxidation on Co and CoB alloy coatings modified with Au nanoparticles

Abstract

The electrochemical oxidation of glucose was investigated on the Co and CoB alloy coatings, which were deposited on the copper substrate (Cu) and subsequently modified with a small amount of Au nanocrystallites. The catalysts were prepared via a simple electroless Co deposition method followed by a spontaneous Au galvanic displacement from the Au(III)-containing solution. The activity of Co and CoB alloy coatings modified with Au crystallites towards the oxidation of glucose was examined by the cyclic voltammetry method. It has been determined that the Co and CoB alloy coatings, which were modified with a small amount of Au crystallites, exhibit a significantly higher activity for the oxidation of glucose as compared to that of bare Au, Co and CoB alloy catalysts. The process of glucose oxidation is significantly shifted to a more negative potential domain at the both Co/Cu and CoB/Cu catalysts modified by Au nanocrystallites, indicating the higher activity of those catalysts as compared to that of the unmodified Co/Cu and CoB/Cu catalysts and the bare Au electrode. It was found that ca. 22 and even 67 times higher glucose oxidation current density values have been obtained at the AuCo/Cu and AuCoB/Cu catalysts, respectively, as compared to those for the unmodified CoB/ Cu and Co/Cu.