Effect of ZnO Nanoparticles Salt Precursors on Structural, Morphological, Optical and MB Photocatalytic Properties Using Hydrothermal Synthesis

ZnO nanoparticles were successfully produced via a simple low cost hydrothermal method using different metal precursors. Zn (CH3COO)2), (Zn (NO3)2) and (ZnCl2) were the source materials. The obtained nanoparticles were investigated by means XRD, SEM and DRS. The XRD exhibited the high crystallinity of the pure ZnO phase with hexagonal wurtzite crystalline structure for all simples excepted for ZnO synthetized from ZnCl2 precursor. The crystallite sizes was estimated in the range of 20-37 nm. The precursor type do not affect the Eg of the nanoparticles. The bandgaps energies were between 3.21-3.22 eV. The type of precursor affect the particles morphology. SEM images revealed different morphologies. The photocatalytic activity of the synthetized ZnO NPs in comparison with that of commercial powder for the methylene blue (MB) degradation under UV irradiation, showed the appropriate activity of nanostructures obtained by Zn (NO3)2 and Zn (CH3COO)2 precursors. The first-order kinetic constant over ZnO from Zn (NO3)2 was 1.9, 3.7 and 1.5 times of ZnO commercial powder, ZnO from ZnCl2 and Zn (CH3COO)2, respectively. The ZnO NPs from Zn (NO3)2 and Zn (CH3COO)2 precursors have the best photocatalytic degradation performance with a degradation rate of 99.3% and 96.4%, respectively. The higher photocatalytic performance was probably due to the larger crystallinity, purity phase and specific morphologies than smaller particle size effect. Thus, the synthetized ZnO nanoparticles by the soft hydrothermal process are a promising candidate for the photocatalytic purposes of dyes from waters.