Electrochemical Synthesis and Photocatalytic Property of Zinc Oxide Nanoparticles

Zinc oxide (ZnO) nanoparticles of varying sizes (20, 44 and 73 nm) have been successfully synthesized by a hybrid electrochemical-thermal method using aqueous sodium bicarbonate electrolyte and sacrificial Zn anode and cathode in an undivided cell under galvanostatic mode at room temperature. The as-synthesized product was characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), Scanning electron microscopy along with Energy dispersive analysis of X-ray (SEM/EDAX), Transmission electron microscopy (TEM), Ultra Violet - Diffuse reflectance spectroscopic methods (UV-DRS). and UV-DRS spectral methods. The as-synthesized compound were single-crystalline and Rietveld refinement of calcined samples exhibited hexagonal (Wurtzite) structure with space group of P6(3)mc (No.186). The band gaps for synthesized ZnO nanoparticles were 3.07, 3.12 and 3.13 eV, respectively, based on the results of diffuse reflectance spectra (DRS). The electrochemically synthesized ZnO powder was used as photocatalysts for UV-induced degradation of Methylene blue (MB). Photodegradation was also found to be function of exposure time and dye solution pH. It has been found that as-synthesized powder has excellent photocatalytic activity with 92% degradation of MB, indicating ZnO nanoparticles can play an important role as a semiconductor photocatalyst.