Seed Mediated Growth of Gold Nanoparticles on Indium Tin Oxide Electrodes: Electrochemical Characterization and Evaluation

Abstract The seed mediated growth of gold nanoparticles on indium tin oxide (ITO) surfaces is described, which provided a new method for the construction of gold nanoparticles‐modified ITO electrodes even without using conventional linker molecules, such as (3‐mercaptopropyl)trimethoxysilane (MPTMS). In this process, ultra‐small gold seeds were formed and anchored on the ITO surfaces first. When the seeds‐deposited ITO surfaces came into contact with the gold growth solution, the growth of gold nanoparticles occurred. The morphology of the as‐prepared modified surface was found to be strongly dependent upon the substrate. On an MPTMS‐silanized ITO, mostly gold nanospheres were formed (Au/MPTMS/ITO).In contrast, on a bare ITO, some high aspect ratio gold nanorods as well as large amounts of gold nanospheres were grown and directly attached (Au/ITO). The as‐prepared two gold nanoparticles‐modified ITO electrodes exhibited different electrochemical characteristics, attributed to the influence of MPTMS molecules. Compared with Au/MPTMS/ITO, the Au/ITO was more efficient in decreasing the heterogeneous charge transfer resistance and improving the reaction reversibility of [Fe(CN) 6 ] 3− /[Fe(CN) 6 ] 4− and exhibited more attractive bioelectrocatalytic properties. Due to the block effect of the thiol monolayer, Au/MPTMS/ITO depressed the selectivity for the determination of epinephrine (EP) in the presence of ascorbic acid (AA) while Au/ITO could improve the detection sensitivity and retain the selectivity.