Facile synthesis CQDs/SnO_2-x/BiOI heterojunction photocatalyst to effectively degrade pollutants and antibacterial...

To remove multitudinous pollutants from wastewater, the design of a highly efficient and multifunctional photocatalyst is necessary. A novel CQDs/SnO_2-x/BiOI photocatalyst (named CSnBI composite) was prepared by combining carbon quantum dots (CQDs), large specific surface area SnO_2-x nanocrystals and BiOI nanocrystals to obtain a compact hybrid structure. TEM and Raman techniques confirmed the structure of CSnBI composite. The photocurrent and EIS showed that the photoexcited electron-hole pairs separation efficiency was improved. As anticipated, novel CSnBI photocatalyst can successfully remove tetracycline, methyl orange, E. coli (Escherichia coli) and S. aureus under a LED light due to the hybridization contaction among CQDs, SnO_2-x and BiOI. The mechanism showed that the introduction of CQDs promoted visible light absorption and efficient separation of photogenerated carriers of SnO_2-x/BiOI heterojunction. The capture experiment and related measurements showed that h⁺, •O₂^- and •OH are active species in the photocatalytic process. This study gave a novel case for facile construction of photocatalysts with tight hybrid structure.