Investigation of electro-oxidation of glucose at gold nanoparticles/carbon composites prepared in the presence of halide ions

Abstract

In this study, the carbon powder supported gold nanoparticles composites (AuNPs/C) were prepared via the chemical reduction method by employing sodium citrate or a complex mixture of glucose and ascorbic acid as reducing agents in the presence of small amounts of different halide ions (Cl^–, Br^–, I^–). The electrocatalytic activity of the synthesized composites was evaluated for the electro-oxidation of glucose in an alkaline medium using cyclic voltammetry, whereas the morphology and composition of composites were characterized using field emission scanning electron microscopy and inductively coupled plasma optical emission spectroscopy. The electrochemical measurements demonstrate the enhanced electrocatalytic performance of the AuNPs/C composites prepared by the help of different reducing agents coupled with halide ions for the electro-oxidation of glucose as compared to that of composites that were synthesized by the use only of the reducing agents barely. The AuNPs/C composites synthesized with the presence of KCl, KBr or KI additive in the reaction mixture generate the increased glucose electro-oxidation current density values; furthermore, the glucose electro-oxidation potential is shifted to more negative values as compared to those obtained on the synthesized composites without halide additive.