Electrochemical properties of aryl-modified gold electrodes

The properties of electrochemically grafted gold electrodes surface have been investigated. Electrografting with 1- and 2-naphthyl, biphenyl and 4-bromophenyl groups yielded strongly attached layers and for the latter, electrochemical quartz crystal microbalance (EQCM) and atomic force microscopy (AFM) measurements showed that a multilayer film of bromophenyl groups was formed. This was confirmed by X-ray photoelectron spectroscopy (XPS). The blocking of electron transfer for several redox probes caused by the aryl-modification was investigated using cyclic voltammetry (CV). Oxygen reduction was studied using a rotating disk electrode (RDE) and the data also revealed a strong inhibition of this process by the attached aryl groups. The stability of these functionalised surfaces points to the strength of the Au–C bonds formed.