Hydro- and solvothermally-prepared ZnO and its catalytic effect on the photodegradation of Reactive Orange 16 dye

Abstract

In this work, zinc oxide powders were obtained by two different techniques: hydro- and solvothermal synthesis starting from Zn(NO3)(2) and Zn(CH3COO)(2), respectively. The influence of synthetic procedure on the structural, microstructural, thermal and photocatalytic properties of the prepared ZnO powders was investigated. Both ZnO samples were further annealed under moderate conditions (300 degrees C) to avoid grain growth and to remove traces of impurities. In all four cases, single-phase hexagonal ZnO was confirmed by X-ray powder diffraction. The morphologies of prepared ZnO powders were different and they varied from rounded nanograins to microrods. All prepared samples showed higher photocatalytic efficiency in the degradation of the textile azo dye Reactive Orange 16 (RO16) than commercial ZnO. In addition, the non-annealed samples had better photocatalytic properties than the commercial Degussa P25 TiO2 powder.