Production, characterization, and photocatalytic properties of Eu:Y₂O₃ nanopowders

Eu:Y₂O₃ nanophosphors (NPs) with different Eu concentrations (3, 5, and 7 at%) were successfully synthesized via the sol–gel method. All synthesized powders had a cubic bixbyite-type crystal structure with space group Ia-3. It was observed they had agglomerated sphere-like morphologies. In addition, a neck formation between the particles, which was the result of the sintering effect at the increasing calcination temperature, was also observed by scanning electron microscopy analysis. Raman and X-ray photoelectron spectroscopy (XPS) analyses confirmed that the Eu dopant entered into the Y₂O₃ host. The XPS peak positions shifted to relatively higher binding energy values with increasing dopant concentration and calcination temperature. Increasing Eu dopant concentration in the host structure also increased the 3+ valence ions. The band gap values of the NPs varied between 4.30 and 4.54 eV. The powders doped with 5 at% Eu was active as photocatalysts and the powders that were synthesized at 800°C exhibited highly photocatalytic activity.