The electrocatalytic oxidation of glucose on the bimetallic Au-Ag particles-modified reduced graphene oxide electrodes in alkaline solutions

• Electrocatalytic oxidation of glucose on bimetallic Au-Ag electrodes in NaOH solution.
• Au and Ag were electrodeposited on reduced graphene oxide (RGO) film to form bimetallic electrodes.
• Catalytic activity and stability of bimetallic electrodes were assesses by cyclic voltammetry.
• Bimetallic electrodes show higher catalytic activity and long-term stability after 500 cycles.
• Glucose oxidation is very sensitive to the loading ratio of Ag to Au in the bimetallic composition.

A given amount of Au and Ag is electrodeposited on the reduced graphene oxide (RGO)/glassy carbon (GC) electrodes to form the Au/Ag/RGO/GC and Ag/Au/RGO/GC electrodes. The electrodeposition potential of Au or Ag is set at–0.30 V (vs. SCE). The electrochemical oxidation of glucose is carried out in NaOH solutions. The experimental results indicate that Ag in the bimetallic Au-Ag electrodes plays an important role in the electrocatalytic oxidation of glucose; the electrochemical behavior of glucose oxidation is very sensitive to the ratio of Ag to Au loading density in the bimetallic composition. The electrocatalytic activity and stability of the bimetallic Au-Ag electrodes are assessed by cyclic voltammetry. The peak current density of the bimetallic Au-Ag electrodes at about 0.24 V is about 4.5 times as large as the gold nanoparticles deposited on the GC electrode reported previously. Enhancing current density is due to the synergetic catalytic effect of Au and Ag. The Ag/Au/RGO/GC electrode lost only 26.2% of its original activity after 500 cycles in a solution consisting of 10.0 mM glucose and 0.10 M NaOH, which is better than that of the Au/Ag/RGO/GC electrode, Ag/Au/GC and Au/Ag/GC electrodes. The reason for this is caused by the electrode structure and RGO used in this work.

Stability of Ag/Au/RGO/GC electrodes with Au loading of 250 μg cm−2 and Ag loading of 57 μg cm−2, in a solution containing 10.0 mM glucose and 0.10 M NaOH, at a scan rate of 50 mV s−1.Figure optionsDownload as PowerPoint slide