BiOBr with oxygen vacancies capture 0D black phosphorus quantum dots for high efficient photocatalytic ofloxacin degradation

A novel BPQDs/OV-BiOBr S-scheme heterojunction photocatalyst with tight interfacial contacts was successfully prepared by hydrothermal deposition of appropriate amount of black phosphorus quantum dots (BPQDs) on bismuth bromoxide with oxygen vacancies (OV-BiOBr). The BPQDs/OV-BiOBr S-scheme heterojunction photocatalysts exhibited excellent degradation activity for ofloxacin (OFLO) under visible light irradiation. The special oxytropism of oxygen vacancies (OVs) on OV-BiOBr was cleverly used to build an oxygen-deficient environment for BPQDs, which significantly enhanced the intimate contact of heterojunction interface and the stability of BPQDs. Meanwhile, the local surface plasmon resonance effect generated by the precipitation of Bi metal on OV-BiOBr significantly improved its photoresponsiveness. The direction of the internal electric field and the special electron transfer mechanism of the S-scheme heterojunction were analyzed in detail by the combination of density functional theory calculation and experiment. This work provides new insights and ideas for the study of OVs regulation of the S-scheme heterojunction.