Investigation of Glucose Oxidation on Gold Nanocrystallites Modified Cobalt and Cobalt-Boron Coatings

Abstract

Herein, the electrochemical oxidation of glucose has been 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 (termed as the AuCo/Cu and AuCoB/Cu catalysts), with the aim to use them as the anode catalysts for direct glucose fuel cells (DGFCs). The catalysts have been prepared via a simple electroless Co deposition method followed by a spontaneous Au galvanic displacement from the Au(III)-containing solution. The activity of the prepared catalysts for the oxidation of glucose in an alkaline medium has been examined by cyclic voltammetry and chrono-techniques.In conclusion, the Co and CoB alloy coatings, which were modified with a small amount of Au nanocrystallites in the range from 11 to 14 µg Au cm–2, exhibit a significantly higher activity for the oxidation of glucose as compared to that of bare Au, Co and CoB alloy catalysts. Furthermore, the process of glucose oxidation has been significantly shifted to more negative potential domain at the both AuCo/Cu and AuCoB/Cu catalysts, indicating the higher activity of the latter catalysts as compared to that of the unmodified Co/Cu and CoB/Cu catalysts and the bare Au electrode. In addition, approximately 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. The prepared AuCo/Cu and AuCoB/Cu catalysts, which have been prepared with very small amount of Au nanocrystallites, seem to be a promising anode material for DGFCs.