Internal electric field and oxygen vacancies synergistically optimized Ba2+ doped SrBi2B2O7 for photocatalytic tetracycline degradation from water

A built-in electric field of the ferroelectric contributes to improving the photoinduced charges separation in the photocatalysis, attracting great attention for the elimination of contaminants from water sources. Herein, a series of Ba2+ doped Sr1-xBaxBi2B2O7 (0 ≤ x ≤ 0.6) were synthesized successfully. Among all samples, Sr0.5Ba0.5Bi2B2O7 showing the most splendid photocatalytic degradation activity, could degrade 94.06% of TC in 30 min, which was about 6.75 and 2.56 times higher than that of the undoped one and BaTiO3, respectively. The synergistic effect of a strong built-in electric field and an appropriate oxygen vacancy was responsible for its high efficiency. The sample remained the superior photocatalytic activity under different reaction parameters including temperature, catalyst dosage, pH, initial ions species, and in the presence of humic acid and different types of water bodies. The different quenching and the controlled atmosphere experiments confirmed that e− and h+ played an essential role in attacking TC molecular. LC-MS revealed its three degradation pathways including the process of demethylation, hydroxylation, and dehydroxylation. The toxicity of formed degradation products reduced significantly. The work is of great significance to construct more ferroelectric photocatalysts and highlights the potential of ferroelectric catalysts for purifying wastewater.