Enhanced Photocatalytic and Photoluminescence Properties of Ce and Dy Co-Doped ZnO Nanoparticles

Cerium and dysprosium co-doped ZnO nanoparticles were synthesized through a simple co-precipitation approach at low temperature. X-ray diffraction was used for the structure and purity analysis of the samples prepared. A hexagonal wurtzite structure was observed with no secondary peaks. The average particle size was ~35 nm. Morphology was studied using scanning electron microscopy. A change in morphology from elongated nanorods to nanoflowers was observed as the concentration of dopants increased. Photoluminescence spectra confirmed the shift of absorption edge towards the visible region of the solar spectrum. Red shift was confirmed by UV–Vis spectroscopy which also revealed the narrowing of bandgap in co-doped samples. The photocatalytic activity of the nanoparticles was evaluated in photodegradation of rhodamine B (RhB) under UV irradiation. The experiment revealed a total degradation of the organic molecules indicated by the elimination of the dye color. The results showed that ZnO photocatalyst, co-doped with cerium and dysprosium (Zn0.90Ce0.05Dy0.05O), exhibited much improved photocatalytic performance (98% degradation) in comparison to un-doped ZnO. The enhanced photocatalytic performance of co-doped samples could be explained by an increase in the amount of surface oxygen vacancies, improved absorption capacity and delayed recombination of photo generated electrons and holes owing to creation of trap states in the bandgap of ZnO.