S-scheme CeO_2-x/AgFeO₂/Ag photocatalysts with impressive activity in degradation of different antibiotics under visible light

In the recent decades, along with human consumption, antibiotics are widely used in animal feed to prevent and treat infectious diseases in livestock. Accordingly, to eliminate these compounds, the developing photocatalytic systems based on visible-light exposure can be a step forward. In the present study, CeO₂ with oxygen vacancies (CeO_2-x) was utilized for the facile fabrication of plasmonic CeO_2-x/Ag/AgFeO₂ photocatalysts. Interestingly, photocatalytic activity of CeO_2-x/Ag/AgFeO₂ (20%) nanocomposite in degradation of tetracycline hydrochloride, azithromycin, metronidazole, and cephalexin was promoted 55.7, 49.1, 76.2, and 71.5-folds as much as CeO₂ and 10.2, 10.5, 21.1, and 47.6-folds in comparison with CeO_2-x, respectively. The surface area of CeO_2-x/Ag/AgFeO₂ (20%) photocatalyst was enhanced 4.41 times compared to the pristine CeO₂. Moreover, the band gaps of CeO_2-x and CeO_2-x/Ag/AgFeO₂ (20%) were 2.69 and 1.90 eV, respectively. The impressive activity was ascribed to the production of a large number of electron/hole pairs, facile segregation and transfer of charges, and extended surface area. Finally, the fabricated plasmonic CeO_2-x/Ag/AgFeO₂ (20%) photocatalyst retained most of its activity after five photocatalytic runs.