Synthesis of gold nanoparticles on diazonium-generated heteroaryl films and their electrocatalytic activities

Abstract In this paper, a novel electrochemical sensing platform has been developed based on the electrodes modified with heteroaromatic molecules decorated with gold nanoparticles (AuNPs). For this purpose, the GC electrodes were first covered with pyridine and phenanthroline rings by using diazonium reduction method. Then, the formation of AuNPs was achieved via the electrochemical reduction of AuCl 4 − ions preadsorbed to the modified GC surfaces. The AuNPs, for comparison, were also prepared on polyphenylene films (PPh) obtained by electrochemical reduction of in situ generated benzenediazonium salts. The existence of the nanoparticles was confirmed by using spectroscopic and electrochemical techniques such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and cyclic voltammetry. The results have shown that the homogeneity of particle distribution is strongly dependent on the nature of the organic film. The electrocatalytic capabilities of the resulting composite films were also assessed both in the anodic and cathodic regions for hydrazine hydrate oxidation and nitrobenzene reduction, respectively. It was found that the AuNPs-modified electrodes showed a significant catalytic effect, since metal nanosites on the surfaces offer a good electrical conductivity and large effective surface area.