Self-Assembly of Bi2Sn2O7/β-Bi2O3 S-Scheme Heterostructures for Efficient Visible-Light-Driven Photocatalytic Degradation of Tetracycline

Fabrication of S-scheme heterojunctions with enhanced redox capability offers an effective approach to address environmental remediation. In this study, high-performance Bi2Sn2O7/β-Bi2O3 S-scheme heterojunction photocatalysts were fabricated via the in situ growth of Bi2Sn2O7 on β-Bi2O3 microspheres. The optimized Bi2Sn2O7/β-Bi2O3 (BSO/BO-0.4) degradation efficiency for tetracycline hydrochloride was 95.5%, which was 2.68-fold higher than that of β-Bi2O3. This improvement originated from higher photoelectron–hole pair separation efficiency, more exposed active sites, excellent redox capacity, and efficient generation of ·O2– and ·OH. Additionally, Bi2Sn2O7/β-Bi2O3 exhibited good stability against photocatalytic degradation, and the degradation efficiency remained >89.7% after five cycles. The photocatalytic mechanism of Bi2Sn2O7/β-Bi2O3 S-scheme heterojunctions was elucidated. In this study, we design and fabricate high-performance heterojunction photocatalysts for environmental remediation using S-scheme photocatalysts.