Synthesis, characterization and photocatalytic property of flame sprayed zinc oxide nanoparticles

In the present study, nanoparticles of zinc oxide (ZnO) were produced by a cost-effective flame-based apparatus. The photocatalytic activity of the ZnO powder was evaluated using the ultraviolet-visible absorbance parameter through the process of photooxidative decomposition of methyl orange (MO). Zinc nitrate (Zn(NO3)2·6H2O), in a concentration of 0.5 M, and urea (CO(NH2)2, in a stoichiometric amount, were used as a source of zinc and fuel, respectively, in the precursor solution. A Bunsen-Meker burner was used for obtaining a pilot flame, where the precursor solution was sprayed, creating the main flame where the reactions occurred, thus producing the powder. Concerning the characterization of the powder, the X-ray diffraction analysis identified zincite as the only crystalline phase in the powder. The scanning electronic microscopy method revealed that the powder was composed of aggregated particles. The application of the transmission electronic microscope and the single line method revealed close results for the crystallite size, corresponding to ≈33 nm. The specific surface area of ZnO powder was 17.34 ± 2.33 m2/g. In the photocatalytic activity evaluation, more than 90% of MO was degraded after 60 min.