Enhanced photocatalytic activity with metal ion doping and co-doping in CeO₂ nanoparticles

In the present work effect of Yttrium (Y) and Zinc (Zn) doping and co-doping on the structural and optical properties of CeO₂ are studied to evaluate its photocatalytic activity for the removal of crystal violet dye. A series of Y (2–10 mol %) and Zn (2–10 mol %) doped CeO₂ are synthesized via co-precipitation route. The synthesized samples were characterized via X-ray diffraction, Transmission electron microscopy, Energy Dispersive X-ray analysis, Fourier transform infrared spectroscopy and Raman spectroscopy. The presence of different functional groups are studied via FTIR and Raman spectroscopy. XRD results confirmed the formation of cubic fluorite structured CeO₂ with average crystallite size ∼ 3–7 nm. Y doping in CeO₂ resulted an increase in the crystallite size, whereas Zn led to decrease in the crystallite size. The photocatalytic activity is studied via UV–visible spectroscopy technique by examining the absorbance spectra. Among the various samples, 8 mol % Y-doped CeO₂ exhibited 100% degradation efficiency within 7 h, while 8% Zn-doped CeO₂ exhibited 100% degradation efficiency towards crystal violet (CV) dye within 5 h under UV–visible illumination. In case of Y, Zn co-doped CeO₂ samples, 100% degradation efficiency towards CV dye was achieved within 3 h under UV–visible light. The present study shows that the metal ion co-doping can lead to enhancement in the degradation efficiency by several folds as compared to doped samples.