Enhanced Photocatalytic Degradation of Rhodamine B Dye by Iron-Doped Europium Oxide Nanoparticles.

As a wide-bandgap rare-earth oxide, Eu 2 O 3 was often utilized as an auxiliary material of other photocatalysts because its photocatalytic performance was limited by the luminescence characteristics of Eu 3+ and low light utilization. In this study, we improved the photocatalytic degradation performance of the Eu 2 O 3 nanoparticles by doping with Fe cations. The Eu 2 O 3 nanoparticles with different Fe-doping concentrations (1, 3, and 5%, noted as EF1.0, EF3.0, and EF5.0, respectively) were synthesized via chemical precipitation and calcination methods. It was found that doping could reduce Eu 2 O 3 's bandgap, which probably originated from the introduction of oxygen vacancies with lower energy levels than the conduction band of Eu 2 O 3 . Compared with the undoped Eu 2 O 3 nanoparticles with a removal efficiency of 22% for degrading rhodamine B dye within 60 min, the photocatalytic degradation efficiencies of EF1.0, EF3.0, and EF5.0 were demonstrated to be improved to 42, 48, and 33%, respectively, and EF3.0's performance was the best. The enhanced photocatalytic performance of the doped samples was related to the oxygen vacancies acting as capture centers for electrons, such that the photogenerated electron-hole pairs were efficiently separated and the redox reactions on the surface of the nanoparticles were enhanced accordingly. Additionally, the enhanced light absorption and broadened spectral band further improved EF3.0's degradation efficiency.