An Efficient Voltammetric Sensor Based on Graphene Oxide-Decorated Binary Transition Metal Oxides Bi(2)O(3)/MnO(2) for Trace Determination of Lead Ions

Herein we present a facile synthesis of the graphene oxide-decorated binary transition metal oxides of Bi(2)O(3) and MnO(2) nanocomposites (Bi(2)O(3)/MnO(2)/GO) and their applications in the voltammetric detection of lead ions (Pb(2+)) in water samples. The surface morphologies, crystal structures, electroactive surface area, and charge transferred resistance of the Bi(2)O(3)/MnO(2)/GO nanocomposites were investigated through the scanning electron microscopy (SEM), power X-ray diffraction (XRD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques, respectively. The Bi(2)O(3)/MnO(2)/GO nanocomposites were further decorated onto the surface of a glassy carbon electrode (GCE), and Pb(2+) was quantitatively analyzed by using square-wave anodic stripping voltammetry (SWASV). We explored the effect of the analytical parameters, including deposition potential, deposition time, and solution pH, on the stripping peak current of Pb(2+). The Bi(2)O(3)/MnO(2)/GO nanocomposites enlarged the electroactive surface area and reduced the charge transferred resistance by significant amounts. Moreover, the synergistic enhancement effect of MnO(2), Bi(2)O(3) and GO endowed Bi(2)O(3)/MnO(2)/GO/GCE with extraordinary electrocatalytic activity toward Pb(2+) stripping. Under optimal conditions, the Bi(2)O(3)/MnO(2)/GO/GCE showed a broad linear detection range (0.01–10 μM) toward Pb(2+) detection, with a low limit of detection (LOD, 2.0 nM). The proposed Bi(2)O(3)/MnO(2)/GO/GCE electrode achieved an accurate detection of Pb(2+) in water with good recoveries (95.5–105%).