Directing nanostructure formation of gold via the in situ under potential deposition of a secondary metal for the detection of nitrite ions

In this work the underpotential deposition of metals such as copper and lead during the electrochemical deposition of gold is investigated to understand the influence that the incorporation of a second metal has on the morphology of gold nanostructures. The incorporation of Pb or Cu, even at concentrations as low as 0.2 %, significantly influence the morphology of the deposit where the formation of elongated structures from a central gold structure is favoured. These nanostructures are characterised by cyclic voltammetry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) and tested for their suitability as a sensing layer for the electrochemical detection of nitrite ions in aqueous solution. A limit of detection of 0.3 µM is achieved with a linear range up to 1 mM which is adequate for the determination of nitrite contained within food products.