Oxygen-vacancy and surface-bromine-grafting dual active sites of Bi2O2(OH)(NO3) nanosheets for excellent photocatalytic pollution degradation

Solar-driven photodegradation technology is a highly promising route for resolving environmental pollutants. However, the performance of photocatalysts is usually limited by the poor light harvesting, the high recombination of photogenerated electron-hole pairs, and the insufficient surface active sites. In this work, thin Bi₂O₂(OH)(NO₃) nanosheets co-modified with oxygen vacancies and bromine-grafting (BNSBr-OV) presented a superb rhodamine B photodegradation efficiency of 98.5 % within 4 h under visible light (λ＞420 nm), which was 8.2 times higher than that of pristine Bi₂O₂(OH)(NO₃). Besides, BNSBr-OV exhibited universal photocatalytic abilities of degrading various antibiotics, including tetracycline hydrochloride, ofloxacin and sodium sulfacetamide. The introduction of oxygen-vacancy and grafted bromine dual active sites can not only improve the light harvesting ability of the photocatalyst, but also promote the migration efficiency of photogenerated carriers, which boosts its photocatalysis performance. This study provides a platform for understanding the dual active sites modified single-crystal material, which potentially offers new design of environmental catalysts for multiple applications.