Enhanced photocatalytic degradation of xanthate over carbon quantum dots embedded on BiOI nanosheets under visible light

Herein, carbon quantum dots (CQDs) were synthesized and embedded onto BiOI nanosheets to form the CQDs/BiOI composite by hydrothermal method and applied to the degradation of xanthate for the first time. The effect of different mass ratios of CQDs and BiOI on the photocatalytic degradation of xanthate was investigated. Compared with pure BiOI, CQDs/BiOI composites exhibited enhanced photocatalytic activity for xanthate degradation under visible light. The highest xanthate degradation was up to 97.9 % at 5 wt% of CQDs to BiOI, and the reaction rate constant was about 12 times that of pure BiOI. The experimental and characterization results revealed the significantly enhanced photocatalytic performance was mainly attributed to the introduction of CQDs, which can greatly improve the segregation efficiency of photogenerated carriers through acting as the electron acceptors. The photocatalyst possessed good reusability for xanthate degradation indicating the great potential in practical application. In addition, the active radicals capturing experiments indicated that •O2− were the main active species, and the possible photocatalytic mechanisms were also discussed in detail. This work provides an effective method to synthesize the promising visible-light-driven photocatalyst for wastewater treatment.