Facile and ultra-sensitive voltammetric electrodetection of Hg in aqueous media using electrodeposited AuPtNPs/ITO.

In this study, we have investigated the use of electrodeposited Au-Pt nanoparticles (AuPtNPs) on indium tin oxide (ITO) for the detection of Hg heavy ions in water samples. The mechanism of AuPtNP electrocrystallization on ITO glass in an aqueous solution containing 0.5 mM HAuCl + 0.5 mM HPtCl is described for the first time. The nucleation mechanism of monometallic AuNPs on ITO was found to be progressive; however, a transition from progressive to instantaneous was observed for bimetallic AuPtNPs at elevated overpotentials. The modified ITOs were then assessed for the electrodetection of Hg in aqueous media. It was shown by differential pulse voltammetry (DPV) that the sensitivity of the constructed AuPtNPs/ITO electrode toward Hg was about 2.08 μA nM. An approximate detection limit of 4.03 nM Hg was achieved, which is below the permissible level of 30.00 nM Hg in drinking water, according to the World Health Organization (WHO). Characterization of AuPt nanostructures was carried out by X-ray diffraction (XRD) patterns, scanning electron microscopy (SEM), and different electrochemical techniques (cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy (EIS)). Our results indicate a good potential of a facile and robust electrochemical assembly for on-site detection of heavy metals in water samples.