Size-controlled Electrocatalysis of Glucose Oxidation in an Alkaline Solution at AuNPS Electrodeposited onto Glassy Carbon Electrodes

The cyclic voltammetric investigation of the electrocatalytic oxidation of glucose in a (5 mM glucose + 0.1 M NaOH) solution has been conducted at Au nanoparticle-modified glassy carbon electrodes. In contrast to the absence of any oxidative current at bare unmodified electrodes, the effective electrocatalytic oxidation of glucose was observed upon the electrodeposition of gold nanoparticles onto the glassy carbon electrode surface. Two distinct oxidation peaks were observed that were attributed to the oxidation of glucose to gluconolactone which in turn was further oxidized at more positive potentials. An interesting size-dependence of the obtained catalytic activities was observed, affecting both the oxidation peak potential and current densities and the best catalyst was shown to be 18 nm Au-GCE with an oxidation peak potential of ca. -0.3 V vs. Ag vertical bar AgCl (Sat. KCl).