Gold-nanoparticle-modified ITO electrodes: effect of preparation methods on the electrochemical performance

Modifying the surface of electrodes with gold nanoparticles (AuNPs) can enhance the electrical performance, but the effects obtained through different modification methods vary. This study compared three modification methods: electrochemical deposition, self-assembly, and sol-gel, to investigate the influence of different preparation strategies on the morphology and performance of AuNPs. Comparative analyses were conducted across three dimensions: morphology, electrochemical performance, and stability. Morphology results indicated that APTES modification significantly enhanced the adsorption density and distribution uniformity of AuNPs. Benefiting from the three-dimensional porous structure of chitosan, the CS/AuNPs/ITO electrode exhibited optimal performance in cyclic voltammetry (CV) and electrochemical impedance spectroscopy tests, with CV peak current (I_p) increasing by up to 46.38% compared to the bare ITO electrode. The results of 50 CV tests in sulphuric acid indicated that the performance of both AuNPs/ITO and APTES/AuNPs/ITO electrodes was improved, with the percentage increase inI_preaching 26.72% and 31.68% respectively. This study elucidates the regulatory mechanisms of different modification methods on electrode microstructure and interfacial properties, providing crucial experimental evidence and strategic guidance for rationally selecting and designing high-performance, highly stable AuNPs-modified electrodes tailored to specific detection environments, such as acidic media or biocompatibility requirements.