Eco-friendly synthesis of ZnO nanoparticles with different morphologies and their visible light photocatalytic performance for the degradation of Rhodamine B

ZnO nanoparticles (NPs) with various morphologies were obtained at low-temperature using an economic and eco-friendly co-precipitation process. X-ray diffraction analysis confirms the formation of pure wurtzite ZnO phase with crystallite size in the 29-32 nm range, while scanning and transmission electron microscopic observations reveal various morphologies (spherical NPs, nanosheets and hexagonal prismatic NPs) as a function of the precursors mixing protocol. The estimated band gap of the as prepared NPs calculated on the basis of Kubelka-Munk function was found to be lower than the known band gap energy of bulk ZnO (3.21-3.26 eV compared to 3.37 eV) which was attributed to oxygen vacancies. Photoluminescence spectra showed that the as-prepared NPs have dissimilar amount of point defects. The strongest intensity of the visible emission was observed for spherical NPs, which implies an increased fraction of oxygen. This sample also exhibited a higher photocatalytic activity for the degradation of Rhodamine B (RhB) under visible light irradiation. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.