Electroless Deposition of Gold on a Glassy Carbon Electrode (GCE) Surface for Selective Detection of Hydrogen Peroxide

Electroless deposition technique was employed to coat the surface of a glassy carbon electrode (GCE) with nanoparticles of gold (AuNPs). Afterward, sulfur (S) components were immobilized onto this AuNPs/GC electrode via an in-situ chemisorption approach that considerably enhanced the catalytic activity, conductivity, and persistent durability of the electrode. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) were used to characterize the modified electrode surface. The experimental results indicated that the S-AuNPs/GC electrode exhibits outstanding catalytic activity for the selective detection of H2O2 (HP). SWV measurements showed that the electrochemical sensor has a wide linear range of 10 to 2500 mu M and a heightened sensitivity of 50.08 mu A mM-1 cm-2. The proposed HP sensor demonstrated adequate repeatability and durability, as well as interference-free quantitative analysis capability. Conventional GCE and Au electrodes are ineffective in carrying out hydrogen peroxide (HP) reduction reactions. Whereas Au NPs modified GCE break down HP to O2 causing O2 interference in the subsequent HP sensing. In such a case, a sulfur adlayer can seal the Au facets responsible for O2 reduction allowing the unblocking of the active sites of Au at -0.93 V enabling a two-electron transfer HP reduction reaction.image