Visible-light-driven photocatalysis degradation of antibiotic pollutants by La-doped CeO₂ nanorods: synergy of La doping and oxygen vacancy

Elemental doping is an effective strategy to enhance photocatalytic activity and extend the light absorption range of single-component photocatalysts. In this work, a series of La-doped CeO₂ nanorods (La-CeO₂-x) with La content of 1 wt%–15 wt% are synthesized by a simple hydrothermal method and further used as photocatalyst for sulfamerazine (SMR) degradation. The prepared La-CeO₂-x nanorods exhibit a great improvement in electron–hole pair migration and visible-light response due to the synergistic effect of abundant oxygen vacancies and heterogeneous elements (La). Consequently, La-CeO₂-x exhibited excellent visible-light photocatalytic performances and chemical stability for SMR degradation, the La-CeO₂-5 sample achieved the highest SMR degradation rate of 81%, which was 3.4 times higher than that of the original CeO₂. Furthermore, three possible degradation pathways of SMR in La-CeO₂ photocatalytic reactions were proposed by liquid chromatography-mass spectrometry technique. Finally, density functional theory calculations were carried out to provide an in-depth understanding of the structure-performance relationships. Considering its excellent properties and better photocatalytic performance, this study demonstrates that La doping in CeO₂ is an effective way to increase oxygen vacancy and improve the photochemical properties of photocatalysts.