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 degrees C exhibited highly photocatalytic activity.