Gold nanoparticles embedded in silica sol-gel matrix as an amperometric sensor for hydrogen peroxide

Abstract

Gold nanoparticles (Au_np) embedded in methyltrimethoxysilane sol-gel (SG) film coated electrode was prepared (GC/SG-Au_np) and characterized. The electrochemical response observed for the GC/SG-Au_np electrode reveals that the dispersed gold nanoparticles in the silicate film are in electrical contact with each other. The potassium ferricyanide redox couple was used as a marker to probe the tunable kinetic barrier of the gold nanoparticles dispersion in the silicate matrix. The GC/SG-Au_np electrode showed good electrocatalytic response for hydrogen peroxide (H₂O₂) reduction without an enzyme or mediator immobilized in the silicate sol-gel film. Linear relationship was observed for H₂O₂ reduction in the concentration range from 2.5 to 45 μ M at the GC/SG-Au_np electrode at an applied potential of -0.5 V and the detection limit was calculated as 3.15 nM. The GC/SG-Au_np modified electrode is simple to prepare and this electrode shows fast response, good stability and reproducible results and could be applied as an amperometric sensor for H₂O₂.