Synthesis of Novel Ternary Photocatalyst Ag3PO4/Bi2WO6/Multi-Walled Carbon Nanotubes and Its Enhanced Visible-Light Photoactivity for Photodegradation of Norfloxacin

Novel nanocomposites of Ag3PO4/Bi2WO6/MWCNTs were prepared via a facile hydrothermal method and in-situ precipitation without the addition of any spherical template. The composites exhibited excellent catalytic activity under visible-light irradiation. Compared with pure Ag3PO4, Bi2WO6, Bi2WO6/MWCNTs, and Ag3PO4/Bi2WO6, ternary Ag3PO4/Bi2WO6/MWCNTs nanocomposites showed the best photocatalytic performance due to the narrow band gap, large specific surface area, high charge separation efficiency, and strong light absorbance in the visible region. Degradation experiments involving norfloxacin (NOR) antibiotics under visible-light irradiation confirmed ideal photocatalytic activity of Ag3PO4/Bi2WO6/MWCNTs nanocomposites. Degradation products of NOR were identified via LC-MS/MS analysis, and a potential photodegradation mechanism of NOR was discussed; results indicated that these antibiotics could be degraded via three pathways. The piperazinyl ring was the most reactive site for hydroxyl radical attacks, followed by stepwise oxidation and further ring-opening. Overall, the composites appear to be promising materials for removing contaminants from water.