A novel strategy to prepare ZnO/PbS heterostructured functional nanocomposite utilizing the surface adsorption property of ZnO nanosheets

To avoid the secondary pollution in the regeneration procedure of conventional water treatment methods with absorbents and develop new functional nanocomposite utilizing the surface adsorption property of ZnO, the ZnO nanosheets prepared via a hydrothermal approach were used to adsorb Pb(2+) in aqueous solution and then hydrothermally treated in aqueous solution containing sulfur source. The products at different stages were characterized with scanning electron micrographs (SEM), energy disperse spectroscopy (EDS), transmission electron microscopy (TEM), selected area electron diffraction (ASED), X-ray diffraction (XRD), Fourier transform infrared spectroscopy spectra (FTIR), photoluminescence (PL) spectra and atomic absorption spectrophotometer. The results proved that the ZnO nanosheets had sorption capacity for Pb(2+) due to the role of surface hydroxy groups of ZnO. Enhanced diffraction peaks of PbS were observed after the ZnO adsorbing Pb(2+) hydrothermally treated. TEM result showed that the ZnO/PbS presents in a nanocomposite heterostructure, in which PbS nanoparticles in a form of single crystal structure were attached to the surface of ZnO proved by selected area electron diffraction. PL spectra indicated that the photoluminescence property in a wide light range was dramatically enhanced and some new peaks clearly appeared. Based on these preliminary experimental results, a simple and environment-friendly strategy to remove toxic heavy metal ions in aqueous solution was proposed. Utilizing the doping effects of nanostructured ZnO, a feasible method to produce the ZnO/PbS nanocomposite with wide range light-responsing property was introduced while the efficient removal of toxic heavy metal ions in aqueous solution was carried out. These resulted multifunctional materials have potential to apply to photocatalytic fields, energy-conversion devices and light-emitting/detecting devices. (C) 2010 Elsevier B.V. All rights reserved.