Electrodeposited Gold Nanoparticles on Graphene Oxide-Modified Carbon Sheets for Enhanced Electrocatalysis and Hydrogen Peroxide Sensing

Abstract

Non-enzymatic electrochemical sensors for hydrogen peroxide (H2O2) are attractive due to their simplicity and stability relying on intrinsic electrocatalytic activity of functional electrode materials. In this work, electrochemical metal deposition was employed fabricate gold nanoparticles (AuNPs) directly on conductive substrate namely bare carbon sheets (CS) and graphene oxide-modified carbon sheets (GO/CS) using the chronoamperometry method. Scanning Electron Microscopy (SEM) confirmed the successful formation of AuNPs on both substrates, with a 57.99% reduction in nanoparticle size observed on GO/CS. The electrocatalytic performance of CS, GO/CS, AuNPs/CS, and AuNPs/GO/CS was evaluated in ferricyanide solution, where the AuNPs/GO/CS electrode exhibited the highest current density and fastest electron transfer. Furthermore, hydrogen evolution reaction (HER) studies in acidic medium demonstrated the enhanced catalytic performance of AuNPs/CS and AuNPs/GO/CS, with current increases of 283.74% and 363.37%, respectively, indicating efficient proton reduction to hydrogen. Additionally, only AuNPs/CS and AuNPs/GO/CS electrodes detected a distinct hydrogen peroxide (H₂O₂) oxidation peak at 0.98 V, with the AuNPs/GO/CS electrode showing a 12.11% higher peak current density. A linear correlation between charge and H₂O₂ concentration was observed over a range of 0.005–10 mM with limit of detection (LOD) 5 µM, highlighting the potential of AuNPs/GO/CS electrodes for sensitive electrochemical sensing applications.