Preyssler Heteropolyacid: A Green and Eco-friendly Catalyst in the Hydrothermal Synthesis of ZnO Nanostructures and their Applications in Photodegradation of Azo Dyes

ZnO nanostructures, including ZnO nano quasi-spheres and nanoplates, were synthesized hydrothermally, from the reaction of zinc acetate, catalyzed by Preyssler type heteropolyacid (H14 [NaP5W30O110]), at 140°C in 48 and 72 hours, respectively. The ZnO nanostructures were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The diameter of nano quasi-spheres, was about 5-10 nm. The nano plates had hexagonal shape showing diameter of 40-60nm. Photocatalytic degradation of Methylene blue and Congo red was effectively performed, using the above prepared ZnO nanostructures, achieving almost 70% decolorization, in short time. First order reaction constants were evaluated as 0.0745 and 0.0746 for Methylene blue and Congo red degradation reactions, respectively, concluding first order kinetics via this protocol.