SYNTHESIS AND STRUCTURAL PROPERTIES OF ZnO NENO-CRYSTALLITES AND THEIR APPLICATION

Abstract

The diamagnetic zinc oxide (ZnO) nano-crystallites were synthesized via the sol-gel method. The X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) were used for structural characterization. The XRD pattern demonstrates that the ZnO nanoparticles (NPs) have a wurtzite structure with an average crystallite size of ~20 nm. The FESEM and EDAX (energy- dispersive x-ray analysis) confirm the particles are in granular, spherical, and rod-like mixed-phase. The absorption spectra show a redshift and observed bandgap (Bg) energy of about 3.17 eV, which might attribute because of the oxygen vacancies. Further, photoluminescence (PL) exhibits dual peaks at wavelengths 430 and 550 nm, which may be assigned due to defects induced at the surface of the NPs. The vibrating sample magnetometer (VSM) study demonstrates the diamagnetic behavior of zinc oxide nanoparticles at 300 K. The photocatalytic effectiveness of the ZnO NPs was examined under UV irradiation by decomposing a Congo red (CR) dye considering as an organic water pollutant. The leading absorption peak of CR dye decreases with the UV irradiation time. The complete decolorization of the CR dye was observed after 150 min with the reaction rate constant of 0.018 min-1.