Photocatalytic degradation of acid orange 7 using Cr-doped CeO₂ nanorods

Cr-doped CeO₂ nanorods were prepared by a co-precipitation method using cerium and chromium nitrates with ammonia solution as the precipitator. The morphology and structure of the synthesized products were characterized by field emission scanning electron microscope, X-ray diffraction, and transmission electron microscopy. The specific surface area of the Cr-doped CeO₂ nanorods (455 m² g⁻¹) is higher than those of CeO₂ nanoparticles (52 m² g⁻¹). X-ray photoemission spectroscopy spectrum confirms the presence of Cr in CeO₂ nanorods. UV–Vis spectra analyzes showed that the Cr-doped CeO₂ nanorods exhibit the absorption band in the visible region. The synthesized products exhibited good photocatalytic activity for the degradation of acid orange 7 under UV–visible light illumination and the pseudo-first order reaction rate constant (k) of 0.250 h⁻¹ for Cr-doped CeO₂ nanorods is higher than 0.142 h⁻¹ of CeO₂ nanoparticles.