CdS/BiOBr Photocatalysts Modified with Monocrystalline Cd Quantum Dots for Sterilization and Degradation of Organic Dyes and Antibiotics

The metal elemental substance quantum dots can provide the surface plasmon resonance (SPR) effect and can establish the electron transport channels between CdS and BiOBr to construct a Z-type heterostructure. The ordered mesoporous BiOBr precursor was first prepared, which was compounded with CdS, and then the monocrystalline Cd quantum dots (QDs) were modified on CdS/BiOBr to prepare the CdS/Cd-QDs/BiOBr photocatalysts. The ordered mesoporous structure increased the specific surface area of the material, and the typical Z-type heterojunctions were constructed between CdS and BiOBr by the electron transport channels constructed from monocrystalline Cd-QDs, which greatly improved the photocatalytic performance of the material. Under simulated sunlight, the CdS/Cd-QDs/BiOBr showed much better photocatalytic performances for Rhodamine B (RhB) and norfloxacin (NOR) photodegradation, which also had the very significant killing effect on E. coli. The prepared CdS/Cd-QDs/BiOBr could achieve a 94.9% degradation rate to RhB in 20 min and a 91.7% degradation rate to NOR in 50 min and killed E. coli almost completely in 60 min. This study provides a reference for the construction of monocrystalline metal quantum dots, the ordered mesoporous structure can improve the adsorption capacity of the material, the monocrystalline metal quantum dots have the higher electron transport capacity, and the above all provide an idea for the construction of photocatalysts.