Preparation of Zinc Oxide-Graphene Composite Modified Electrodes for Detection of Trace Pb(II)

Abstract

ZnO nanotubes were prepared via electrospinning Zn(Ac)2-polyacrylonitrile-polyvinyl pyrrolidone precursor, followed by thermal decomposition of the above polymers from the precursor fibers. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) characterization confirmed that the as-prepared ZnO nanofibers presented the hollow nanotube form, which was composed of ZnO nanoparticles with the size of about 40 nm in wurtzite crystal structure. By mixing with reduced grapheme oxide (RGO), the obtained ZnO-RGO composite modified glassy carbon electrode (ZnO-RGO/GCE) was successfully constructed by drop-coating, and used for the determination of Pb2+ in water. The sensitive response of the ZnO-RGO/GC electrode to Pb2+ in solution was demonstrated by square wave stripping voltammetry, with the response potential at −0.4 V. Under the optimized conditions, a good linear relationship between peak current and Pb2+ concentration was obtained in the range of 2.4 × 10−9–4.8 × 10−7 M (R = 0.9970) by 10 min preconcentration at −1.0 V in 0.1 M HAc-NaAc buffer solution (pH 4.6). The detection limit was 4.8 × 10−10 M (S/N ≥ 3). The ZnO-RGO/GC electrode had good stability. The practical analytical application of the ZnO-RGO modified electrode was assessed by the measurement of the actual water sample and the result was consistent with that obtained by ICP-MS.