Antibiotics photodegradation over recycling Z-scheme Bi2Ti2O7@Bi2S3/PU with super-efficiency: DFT calculation, toxicity of oxytetracycline intermediates and photoactivation mechanism

Inspired by the high sustainability, energy saving, cleanliness of photocatalysis (PC) with respect to antibiotics decomposition, we developed a stable, highly efficient Bi 2 Ti 2 O 7 @Bi 2 S 3 /polyurethane (BTO@Bi 2 S 3 /PU) photocatalytic system. It exhibited the best degradation performance with the removal of 82.08 % oxytetracycline (OTC) within 180 min under the optimal reaction parameters. Systematic characterization of BTO@Bi 2 S 3 /PU revealed its wider light-harvest capacity, higher electron–hole (e − –h + ) separation efficiency, lower interface resistance, and better redox potential in heterojunction. Based on electrochemical characterization and density functional theory calculation, the construction of Z-scheme BTO@Bi 2 S 3 photocatalyst substantially optimized the band structure. Moreover, the redox cycles of Bi 3+ /Bi 5+ and Ti 4+ /Ti 3+ further enhanced the charge transfer rate during the photoactivation process. For the OTC photodegradation pathways, ·OH, h + , ·O 2 − , and 1 O 2 dominated the pollutant decomposition and the toxicity of intermediates were decreased. Overall, the BTO@Bi 2 S 3 /PU photocatalytic system may provide a universal and stable technique for advanced photoheterojunction applications and wastewater purification.