Construction of dual Z-scheme Bi2WO6/g-C3N4/black phosphorus quantum dots composites for effective bisphenol A degradation.

In this work, a novel dual Z-scheme Bi2WO6/g-C3N4/black phosphorus quantum dots (Bi2WO6/g-C3N4/BPQDs) composites were fabricated and utilized towards photocatalytic degradation of bisphenol A (BPA) under visible-light irradiation. Optimizing the content of g-C3N4 and BPQDs in Bi2WO6/g-C3N4/BPQDs composites to a suitable mass ratio can enhance the visible-light harvesting capacity and increase the charge separation efficiency and the transfer rate of excited-state electrons and holes, resulting in much higher photocatalytic activity for BPA degradation (95.6%, at 20 mg/L in 120 min) than that of Bi2WO6 (63.7%), g-C3N4 (25.0%), BPQDs (8.5%), and Bi2WO6/g-C3N4 (79.6%), respectively. Radical trapping experiments indicated that photogenerated holes (h+) and superoxide radicals (•O2-) played crucial roles in photocatalytic BPA degradation. Further, the possible degradation pathway and photocatalytic mechanism was proposed by analyzing the BPA intermediates. This work also demonstrated that the Bi2WO6/g-C3N4/BPQDs as effective photocatalysts was stable and have promising potential to remove environmental contaminants from real water samples.