0D/2D CQDs/Bi7O9I3 composite with high photocatalytic disinfection performance under visible light

The development of sustainable and efficient photocatalysts for water disinfection has always been the challenge. Herein, 0D CQDs are grown in situ onto 2D Bi7O9I3 microsheets successfully for the first time, constructing a series of CQDs/Bi7O9I3 composite catalysts for photocatalytic disinfection. Compared with pure Bi7O9I3, the optimal 2-CB exhibits the highest photocatalytic antibacterial (99.99%) and degradation activity, which is attributed to the synergistic effect of CQDs and Bi7O9I3. CQDs can be used as photosensitizers to enhance light absorption and electron acceptors to promote the separation of photogenerated charge carriers. The leakage of K+ ions and the structural destruction of the cell membrane cause bacteria death. Free radical trapping experiment proves that h(+) plays a critical role on bacteria inactivation. The possible photocatalytic disinfection mechanism is also proposed. This work sheds light on designing highly-efficient photocatalysts toward water disinfection.