Carbon dots sensitized 2D-2D heterojunction of BiVO4/Bi3TaO7 for visible light photocatalytic removal towards the broad-spectrum antibiotics

Highlights: • Fabrication of C-dots modified 2D-2D heterojunction of BiVO4/Bi3TaO7 was achieved. • C-dots/BiVO4/Bi3TaO7 shows highly stable photocatalytic removal for antibiotics. • C-dot could accelerate electron transport by its good electrical conductivity. • C-dot could extend solar light harvesting by its distinctive up-conversion effect. • C-dots/BiVO4/Bi3TaO7 is potential effective to remove antibiotics in wastewater. -- Abstract: Focused on the removal of the complicated residual antibiotic in aqueous environment, in this work, a novel carbon dots (C-dots) sensitized 2D-2D heterojunction of BiVO₄/Bi₃TaO₇ were assembled through a simple hydrothermal process. The characteristic by TEM, SEM, and XPS confirmed C-dots evenly anchored on the surface of BiVO₄/Bi₃TaO₇ heterojunction. The as-prepared C-dots/BiVO₄/Bi₃TaO₇ showed superior performance for the degradation of the various antibiotics under visible light illumination. When the concentration of C-dots in the composite is 3 wt.%, the photodegraded rates are obtained to be 91.7%, 89.3%, 87.1%, for tetracycline (TC), amoxicillin (AMX) and ciprofloxacin (CIP), respectively, without significant deactivation during consecutive ten recycle experiments. Furthermore, by assessing the antibiotics mixture solution of TC, AMX and CIP, it is proposed that the prepared samples are potentially effective for the wastewater effluents. A probable mechanism was reasonably proposed. The improved photocatalytic activities could be attributed to the unique construction of the C-dots mediated heterojunction, which could expedite electron migration, improve light harvesting capacity and enhance charge separation efficiency. The present investigation may provide a new perspective to design C-dots mediated heterojunction which could be a potential visible-light-driven photocatalysts for the better practical applications in remediation of broad-spectrum antibiotic residues.