Carbon quantum dots sensitized ZnSn(OH) ₆ for visible light-driven photocatalytic water purification

In this study, carbon quantum dots (CQDs) decorated ZnSn(OH) ₆ (ZSH) micro-spheres with uniform solid, hollow and yolk-shell structures were successfully synthesized by an etching-second growth strategy and facile hydrothermal method. Compared with pure ZSH, ZSH@CQDs composites exhibited obviously enhanced photocatalytic activities for both degradation of organic pollutant and disinfection of staphylococcus aureus. In CQDs decorated composites, ZSH@CQDs with yolk-shell structure presented 70.4% of RhB degradation efficiency under visible light irradiation within 8 h, which was about 10 times higher than that of ZSH samples. ZSH@CQDs with yolk-shell structure also manifested the best photocatalytic inactivation performance under visible light illumination, which could achieve water purification of 100% bacteria disinfection within 16 h. The enhanced photocatalytic activities might be attributed to the unique up-conversion property of CQDs, as well as its efficient charge separation, and a possible mechanism was reasonably proposed. This work could provide a new perspective to design efficient CQDs decorated photocatalysts for water purification.