Gold nanoparticle/alkanedithiol conductive films self-assembled onto gold electrode: Electrochemistry and electroanalytical application for voltammetric determination of trace amount of catechol

This paper describes novel electrochemical properties of gold nanoparticles/alkanedithiol conductive films and their electroanalytical applications for voltammetric determination of trace amount of one kind of environmental pollutants, catechol. The conductive films are prepared by closely packing 12-nm diameter gold nanoparticles (Au-NPs) onto Au electrodes modified with the self-assembled monolayers (SAMs) of alkanedithiols (i.e., HS(CH₂)_nSH, n = 3, 6, 9). The assembly of the Au-NPs onto the SAM-modified electrodes essentially restores the heterogeneous electron transfer between Au substrate and redox species in solution phase that is almost totally blocked by the SAMs and, as a result, the prepared Au-NP/SAM-modified electrodes possess a good electrode reactivity without a remarkable barrier toward the heterogeneous electron transfer. Moreover, the prepared Au-NP/SAM-modified electrodes are found to exhibit a largely reduced interfacial capacitance, compared with bare Au electrode. These electrochemical properties of the Au-NP/SAM-modified electrodes essentially make them very useful for electroanalytical applications, which is illustrated by voltammetric determination of trace amount detection of environmental pollutant, catechol.