Improvement of the optical and photocatalytic properties of ZnAl2O4: 1% La3+, x% Pb2+ nanoparticles synthesized by citrate sol-gel route

Abstract Samples of pure zinc aluminate (ZnAl2O4) and doped both with lead (Pb2+) at different ratios (0, 0.5, 1, 1.5, 2 and 2.5% mol) and a constant amount of lanthanum (La: 1% mol), were prepared by the citrate sol-gel technique, and then annealed at 900°C for 2h. In order to study the structural, optical and thermal properties; different characterization methods were used, such as: powder X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), differential scanning calorimetry (DSC), TGA, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The Analyzes by XRD revealed the presence of the cubic single phase ZnAl2O4 for all samples, with a crystallites size between 19 and 25 nm. These results were confirmed using FTIR, Raman spectroscopy and SEM. Also, photocatalytic study for different samples of ZnAl2O4 shows that they can be used like as photocatalyst and good adsorbents for degradation of Hexamethyl crystallized violet dye in aqueous solution.