BiOBr/FeMoO4 composite achieves oxygen vacancy concentration adjustment to promote persulfate activation degradation of organic pollutants in saline water

The investigation about the mechanism of crystal plane regulation on the generation of oxygen vacancies remains a challenge. In this paper, BiOBr/FeMoO₄ composites were synthesized by precise control of crystal plane growth, and it exhibited the enhanced concentration of oxygen vacancies due to lower formation energy of oxygen vacancies. The composite performs higher photo-Fenton-like ability for degrading oxytetracycline hydrochloride (OTC). Structural analyses and theoretical calculations reveal that crystal plane regulation induces significant changes in oxygen vacancy concentration. The BiOBr/FeMoO₄/peroxydisulphate (PDS) /light system, which dominated by the non-radical pathway, degraded 96.8 % ± 1.0 % of OTC within 30 min. The activation mechanism of the system and the degradation pathway of OTC were elucidated. The intermediates in the degradation process of OTC were evaluated using liquid chromatograph-mass spectrometer (LC-MS), toxicity evaluation software tool (T.E.S.T) and soybean germination experiments. This work offers novel insights into the pivotal role of crystal plane directional regulation in the quantitative generation of oxygen vacancies.