Cobalt selenide nanoflake decorated reduced graphene oxide nanocomposite for efficient glucose electro-oxidation in alkaline medium

Abstract

A simple one pot hydrothermal procedure for the synthesis of cobalt selenide (CoSe) decorated reduced graphene oxide (rGO) is reported along with the application of this hybrid material as a new electrocatalyst for glucose oxidation. In alkaline media, glassy carbon electrodes modified with CoSe–rGO composite dispersed in chitosan display excellent reproducibility for the determination of glucose along with a high sensitivity of 480 μA mM⁻¹ cm⁻², a linear dynamic range of up to 10 mM, a lower limit of detection of 2.5 μM and an exceptionally high maximum current density of 5.41 ± 0.03 mA cm⁻². Bulk electrolysis measurements carried out with the CoSe–rGO/chitosan modified glassy carbon plate revealed that the oxidation of glucose can proceed beyond the formation of gluconolactone with formate detected by ¹H-NMR and CO₂ detected by gas chromatography; the latter result showing the ability to achieve complete oxidation of glucose. Studies with ascorbic and uric acid showed that their interference with respect to glucose measurement either is negligible or can be overcome.