Abstract
Ph.D. (Chemistry)
The quest for clean drinking water devoid of organic pollutants has been the motivation for most researchers nowadays as millions of people from developing countries do not have access to this necessity. This has prompted the use of conventional techniques to address these problems. However, most of these techniques are not sustainable for a long period because of high capital requirement. In addition, most of these techniques are complicated as some produce secondary products, which required further treatment with additional cost. Photocatalysis using semiconductor materials (ZnO, TiO2 and ZrO2) is the best alternative for mineralising organic pollutants from complex forms to a smaller amount of less harmful substances like water and carbon dioxide. The problem with these semiconductors is their large band gaps coupled with their photoactivity in the ultraviolet range and the electron-hole pairs recombination. Therefore to achieve complete photocatalysis in the visible-light range, rare-earth metals (Ce3+, La3+, Gd3+, Dy3+, Sm3+ and Nd3+) and carbon material like graphene oxide were incorporated into the semiconductors. In this study, sol-gel and co-precipitation methods were used to synthesise metal oxide semiconductors modified with rare earth metals and the nanostructures obtained were decorated on graphene oxide sheets. The structures, morphologies, photocatalytic performances, and optical activities of the as-synthesised nanocomposites (Nd-TiO2-GO, Nd-ZnO-GO, La-TiO2-GO, Nd-ZnO-GO and Ce-ZrO2-GO) were analysed using advanced technologies such as Raman spectroscopy (RS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultraviolet-visible (UV-Vis) spectroscopy. The results obtained for various nanocomposites are described with their results from hereon...