Investigation of Photocatalytic and Photoluminescent Properties of a Novel Multifunctional Near-UV Excited NanoStucture CeO2:0.1Dy0.1Ho

Abstract

In this study, Dy³⁺ doped and Ho³⁺ co-doped materials synthesized by the sol-gel method at different temperatures were investigated. The structural and optical properties were characterized by an x-ray powder diffract meter, thermal analysis system, scanning electron microscopy, Raman spectroscopy, FT-IR, UV-vis spectroscopy, and photoluminescence spectrophotometer. The photocatalytic performance, crucially contingent on the sintering temperature, was systematically evaluated using malachite green and methylene blue as model pollutants. Remarkably, the highest efficiency, registering an impressive 90%, was achieved for methylene blue when sintered at 1000 °C. For malachite green, a substantial efficiency of 62% was attained at a sintering temperature of 800 °C. The corresponding optical band gap, a pivotal parameter influencing photocatalytic activity, was determined to be 2.43 eV. Under the near-UV excitation at 318 nm, the CeO₂:0.1Dy0.1Ho phosphor emitted photoluminescence with dominating emissions at 475 nm (blue), 559 nm (green) and 663 nm (red) corresponding to ⁴F_9/2→⁶H_15/2 (blue) transition of Dy³⁺ ions, ⁵F_4,⁵S₂→⁵I₈ (green) and ⁵F₅→⁵I₈ (red) transitions of Ho³⁺ ions, respectively.