Controlled synthesis of dendritic gold nanostructures by graphene oxide and their morphology-dependent performance for iron detection in coastal waters

Abstract

A facile and effective method was introduced for the controlled synthesis of dendritic gold nanostructures on the electrode via a simple electrochemical route in which graphene oxide (GO) was used as a morphology-controlling agent. The oxygen-containing groups on GO controlled not only the diffusion of AuCl₄⁻ ions but the subsequent generation of gold nuclei at the initial stage and the growth direction of the gold nanocrystals in the electrochemical synthesis process. The morphology-dependent electrochemical sensing ability of gold nanostructures was discussed in detail on the basis of control experiments related to the concentration of GO, HAuCl₄, and the electrodeposition time. It could be a straightforward and controllable method for improving the nanoparticles' electrochemical performance. The unique nanostructure and excellent electro-catalytic properties of the dendritic gold nanostructures made the modified electrode an excellent choice for differential pulse voltammetric determination of Fe(III). The modified electrode exhibited a linear response to Fe(III) in the 7 nM to 1 μM concentration range, with a lower detection limit of 1.5 nM. The modified electrode was successfully applied to the sensitive determination of iron in local coastal waters.