Construction of a novel two-dimensional AgBiO₃/BiOBr step-scheme heterojunction for enhanced broad-spectrum...

Efficient S-scheme heterojunction photocatalysts were prepared through in situ growth of AgBiO₃ on BiOBr. The self-assembled hierarchical structure of AgBiO₃/BiOBr was formed from flower-like AgBiO₃ and plate-like BiOBr. The optimized AgBiO₃/BiOBr heterojunction possessed excellent visible-light photocatalytic degradation efficiency (83%) for ciprofloxacin (CIP) after 120 min, with 1.46- and 4.15-times higher activity than pure AgBiO₃ and BiOBr, respectively. Furthermore, the removal ratio of multiple organic pollutants including tetracycline, Rhodamine B, Lanasol Red 5B and methyl orange was also investigated. Environmental interference experiments demonstrated that high pollutant concentrations, low photocatalyst dose and the addition of ions (SO₄ ^2-, PO₄ ^3-, HPO₄ ^2-, H₂PO₄ ^-) inhibited the photocatalytic activities. Subsequently, a simultaneous degradation experiment showed the competitive actions between CIP and RhB for radicals, decreasing the photocatalytic activity of CIP. Furthermore, trapping and electron spin resonance experiments showed that h⁺ and ˙O₂ ^- played a certain role in the degradation process and that ˙OH acted as assistant.