Gold nanoparticles supported on zirconium, tin and ruthenium oxides for reagentless electrochemical sensing of hydrogen peroxide

Abstract

We demonstrate a simple method for the fabrication of metal oxide (M-Ox) supported gold nanoparticle (AuNP) composite films (M-Ox–AuNP) by mechanical and electrochemical methods on solid surface for reagentless electrochemical sensing of hydrogen peroxide (H₂O₂). The method involves anchoring the M-Ox onto the solid surface using nafion binder followed by electrodeposition of AuNPs to form M-Ox–AuNP composites. The M-Ox used are ruthenium (RuO₂), tin (SnO₂) and zirconium (ZrO₂) oxides. Studies reveal that the M-Ox–AuNP mimics the enzyme kinetic behaviour and Michaelis–Menten (MM) kinetic constants, K_M and K_c, are evaluated. The K_M values observed for the ZrO₂–AuNP, RuO₂–AuNP and SnO₂–AuNP composites are 1000, 10.1 and 2.3 mM, respectively. The highest K_M of the ZrO₂–AuNP is correlated with its largest band gap energy change (1.1 eV) and highest electrochemical activities. These are further supported by the increased crystalline nature and ligand-to-metal charge transfer processes confirmed by UV-visible (UV-vis), Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared (FTIR) and X-ray diffraction (XRD) techniques. These M-Ox–AuNP composites are applied for H₂O₂ sensing in commercial antiseptic and milk samples.