Synthesis of Ce doped nanostructured ZnO films and photocatalytic activity

Industrial water pollution has become an increasingly serious problem in recent years. Semiconductor photocatalysts are preferred as an alternative process to solve this problem. Among these, ZnO photocatalysts have recently come to the forefront as a promising catalyst in wastewater treatment due to their cost effective, abundant availability in nature and being an environmentally friendly material. In this thesis, photocatalytic activities of pure ZnO and ZnO:Ce (2 %, 4 %, 6 %, 8 %) films produced by Ultrasonic Spray Pyrolysis (USP), which is an economical method, were determined by degradation of methylene blue (MB) dye. It is aimed to improve the photocatalytic activity by doping ZnO with rare earth elements (Gd, Sm, Ce and Er etc.). The effect of cerium (Ce) doping on the optical, structural, surface properties and photocatalytic activity of the films was investigated using UV-visible spectrophotometry, spectroscopic ellipsometry (SE), XRD, atomic force microscopy (AFM), field emission scanning microscopy (FESEM) and photoluminescence spectrometry (PL). In the morphology analysis of the films, a chrysanthemum-like nanoflower structure was observed as a result of Ce doping. Photoluminescence spectra were taken to determine the trap levels formed in the structure of ZnO:Ce films to be used in photocatalytic applications. As a result, it was found that the photocatalytic properties of ZnO:Ce films vary significantly depending on the surface morphology of the photocatalyst and surface defects (zinc interstitial, oxygen vacancies). Photocatalytic activity measurements showed that the film with the highest degradation efficiency value was 8 % Ce doped ZnO films. Evaluating all the results, it was determined that Ce doping had a significant effect on photocatalytic activity applications. Keywords: ZnO:Ce, Ultrasonic Spray Pyrolysis Method, Photoluminescence, Photocatalytic.