In Situ Interfacial Engineering of CeO2/Bi2WO6 Heterojunction with Improved Photodegradation of Tetracycline and Organic Dyes: Mechanism Insight and Toxicity Assessment

The construction of heterojunction photocatalysts is an auspicious approach for enhancing the photocatalytic performance of wastewater treatment. Here, a novel CeO₂/Bi₂WO₆ heterojunction is synthesized using an in situ liquid-phase method. The optimal 15% CeO₂/Bi₂WO₆ (CBW-15) is found to have the highest photocatalytic activity, achieving a degradation efficiency of 99.21% for tetracycline (TC), 98.43% for Rhodamine B (RhB), and 94.03% for methylene blue (MB). The TC removal rate remained at 95.38% even after five cycles. Through active species capture experiments, •O₂ ^-, h⁺, and •OH are the main active substances for TC, RhB, and MB, respectively. The possible degradation pathways for TC are analyzed using liquid chromatography-mass spectrometry (LC-MS). The photoinduced charge transfer and possible degradation mechanisms are proposed through experimentation and density functional theory (DFT) calculations. Toxicity assessment experiments show a significant reduction in toxicity during the TC degradation process. This study uncovers the mechanism of photocatalytic degradation in CeO₂/Bi₂WO₆ and provides new insights into toxicity assessment.