Insight into tetracycline photocatalytic degradation mechanism in a wide pH range on BiOI/BiOBr: Coupling DFT/QSAR simulations with experiments

A single hydrothermal reaction was used to create BiOI/BiOBr composites, which demonstrated good sunlight-driven photocatalytic degradation activity of tetracycline (TC) over a broad pH range and the degradation efficiency can be stable at about 90%. Moreover,·O2- has been identified as the most important active ingredient in the photocatalytic system. Density functional theory (DFT) calculations were used to investigate the electron transfer mechanism of BiOX heterojunctions on a molecular scale, as well as to propose possible photocatalytic degradation mechanisms and reaction sites for tetracycline in different deprotonated forms at a wide range of pH values. The quantitative structure-activity relationship (QSAR) was also used to assess the toxicity of the intermediates. In summary, this study presents new concepts for investigating the photodegradation behavior of antibiotics throughout a wide pH range, which is predicted to be employed for surface water remediation.