Solvothermal-based synthesis of barium stannate nanosheets coupled with copper manganate nanoparticles for efficient photooxidation of tetracycline under visible light

Photocatalytic oxidation of antibiotic waste over semiconducting heterojunction photocatalysts is considered eco-friendly because it is simple and operates under light irradiation. In this work, we apply a solvothermal-based process for obtaining high surface area barium stannate (BaSnO₃) nanosheets followed by adding 3.0-12.0 wt% of spinel copper manganate (CuMn₂O₄) nanoparticles to form n-n CuMn₂O₄/BaSnO₃ heterojunction photocatalyst after calcination process. The CuMn₂O₄-supported BaSnO₃ nanosheets exhibit mesostructure surfaces with a high surface area range of 133-150 m²g^-1. Moreover, introducing CuMn₂O₄ to BaSnO₃ shows a significant broadening in visible light absorption range due to bandgap reduction down to 2.78 eV in 9.0% CuMn₂O₄/BaSnO₃ compared to 3.0 eV for pure BaSnO₃. The produced CuMn₂O₄/BaSnO₃ is used for photooxidation of tetracycline (TC) in water as emerging antibiotic waste under visible light. The photooxidation of TC exhibits the first-order reaction model. The specific dose of 9.0 wt% CuMn₂O₄/BaSnO₃ at 2.4 gL^-1 displays the highest-performed and recyclable photocatalyst for total oxidation of TC after 90 min. This sustainable photoactivity is attributed to the improved light harvesting and charges migration upon coupling between CuMn₂O₄ and BaSnO₃.