Effect of the Oxygen Vacancies in CeO₂ by the Ce³⁺ Incorporation to Enhance the Photocatalytic Mineralization of Phenol

In this paper, the phenol mineralization by Ce³⁺-doped CeO₂ by photocatalysis at room temperature, is shown for the first time. The photocatalytic behavior of CeO₂ was improved through the incorporation of Ce³⁺ into its crystalline lattice. The materials were prepared by the precipitation method at low temperatures varying the Ce⁴⁺:Ce³⁺ molar ratio of the precursors during the synthesis process. It is worth noting that, the synthesized photocatalysts did not carry out a thermal treatment after their preparation. The results obtained from Raman analysis demonstrated the formation of oxygen vacancies by the incorporation of Ce³⁺. The improvement of the photocatalytic activity was attributed to an optimal content of Ce³⁺ which promoted structural defects (such as oxygen vacancies). Radical species, such as O₂^.−, are mainly formed during the photocatalytic process, which are probably the main responsible for inducing the mineralization process of the studied pollutant.