A sensitive electrochemical Hg2+ ions sensor based on polypyrrole coated nanospherical platinum

Abstract

We report the synthesis and characterization of polypyrrole coated on nanospherical platinum (Pt/PPy NSs) composites for the detection of mercury ions. The synthesis was completed via the direct reduction of potassium tetrachloro platinate(II) aqueous solution in the presence of pyrrole monomers in NaOH. X-ray diffraction and field emission scanning electron microscopy results indicated that the Pt cations were completely reduced to Pt with the concurrent formation of Pt/PPy NSs nanospherical morphology, respectively. The electrochemical properties of Pt/PPy NSs electrode were studied by cyclic voltammetry, differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy. From the DPV results, a linear working range for the concentration of mercury ions between 5 to 500 nM with LOD 0.27 nM (S/N = 3) was obtained. The sensitivity of this linear segment is 1.239 μA nM⁻¹ cm⁻². The interference from Ag⁺, Fe²⁺, Mn²⁺, K⁺, Pd²⁺, Cu²⁺, Ni²⁺, Pb²⁺, Sn²⁺ and Zn²⁺ was negligible, thus is a bright prospect for the electrochemical detection of Hg(II).