S-Scheme photocatalyst TaON/Bi2WO6 nanofibers with oxygen vacancies for efficient abatement of antibiotics and Cr(VI): Intermediate eco-toxicity analysis and mechanistic insights

Enlightened by natural photosynthesis, developing efficient S-scheme heterojunction photocatalysts for deleterious pollutant removal is of prime importance to restore environment. Herein, novel TaON/Bi2WO6 S-scheme heterojunction nanofibers were designed and developed by in-situ growing Bi2WO6 nanosheets with oxygen vacancies (OVs) on TaON nanofibers. Thanks to the efficiently spatial charge disassociation and preserved great redox power by the unique S-scheme mechanism and OVs, as well as firmly interfacial contact by the core-shell 1D/2D fibrous hetero-structure via the in-situ growth, the optimized TaON/Bi2WO6 heterojunction unveils exceptional visible-light photocatalytic property for abatement of tetracycline (TC), levofloxacin (LEV), and Cr(VI), respectively by 2.8-fold, 1.0-fold, and 1.9-fold enhancement compared to the bare Bi2WO6, while maintaining satisfactory stability. Furthermore, the systematic photoreaction tests indicate TaON/Bi2WO6 has the high practicality in the elimination of pollutants in aquatic environment. The degradation pathway of tetracycline and intermediate eco-toxicity were determined based on HPLC–MS combined with QSAR calculation, and a possible photocatalytic mechanism was elucidated. This work provides a guideline for designing high-performance TaON-based S-scheme photocatalysts with defects for environment protection.