resumo
Mesoporous ZnO materials have been synthesized through chemical deposition of different precursors from aqueous or water-ethanol solutions followed by their thermal decomposition at 400°C in air. The microstructure and morphology of the precursors and obtained ZnO powders were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and nitrogen adsorption-desorption (BET) methods. The structure of the precursor and physico-chemical properties of final zinc oxide powders were shown to be considerably influenced by the presence of Cl- ions and ethanol in solution. In water-ethanol solutions, Zn5(OH)8Cl2H2O or Zn5(OH)8(NO3)2(H2O)2 precursors are formed, while ZnO particles are directly deposited from aqueous solution. The photocatalytic activity of the synthesized ZnO materials was evaluated by the decolorization of Rhodamine B (RhB) upon UV irradiation. The ZnO powders have demonstrated high photocatalytic efficiency, enabling decomposition of 81.4-97.4 % RhB within 3 hours. The increased photocatalytic efficiency of ZnO prepared by annealing of Zn5(OH)8Cl2H2O precursor or deposited directly from aqueous chloride-containing solutions can be originated from the presence of Cl-containing compounds remaining after thermal treatment of simonkolleite as well as from introduction of Cl-dopant in ZnO. © 2017 Elsevier Ltd.
autores
Maltanava, H; Poznyak, S; Ovodok, E; Ivanovskaya, M; Maia, F; Kudlash, A; Scharnagl, N; Tedim, J
nossos autores
João Tedim
Professor associadoProjectos
agradecimentos
We acknowledge funding from SMARCOAT project. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sk_odowska-Curie grant agreement No 645662. This work was also developed in the scope of the project CICECO – Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (Ref. FCT UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement. JT thanks FCT for the research grant IF/00347/2013.