Visible-driven photocatalytic activity and stability of Bi₂O₃ enhanced by CQDs

Bi₂O₃ is an excellent visible light photocatalyst. However, the structural instability limits its activity and engineering application. To enhance the activity and stability, the composite of CQDs and Bi₂O₃ was constructed by solvothermal method, and the physical–chemical properties of prepared composite were characterized using XRD, TEM, XPS, FTIR and TPC. As the target pollutant, bisphenol A (BPA) was used to investigate the photocatalytic activity and the stability of CQDs@Bi₂O₃ by photodegradation experiment under the irradiation of simulated visible light, and butyl xanthate was used to prove the applicability by mung bean sprouts. As the results, the existence of CODs obviously promoted the photocatalytic activity of Bi₂O₃:10% CQDs@Bi₂O₃ could remove 93.7% of BPA in 120 min, and the reaction constant rate was almost 1.5 time of pure Bi₂O_3. Moreover, 10%CQDs@Bi₂O₃ could effectively remove butyl xanthate and greatly reduce the growth toxicity on mung bean sprouts. After doping with CQDs, the electron transfer path on the surface of the catalyst could effectively inhibit the electron–hole composite and improve the stability of the composite to a certain extent.