β-NaYF4:Yb,Er,Gd nanorods@1T/2H-MoS2 for 980 nm NIR-triggered photocatalytic bactericidal properties

A β-NaYF4:Yb,Er,Gd nanorods@1T/2H-MoS2 nanocomposite was fabricated and used for photocatalytic sterilization under illumination from single near-infrared (NIR) light. Approximately 99.3% of Escherichia coli were killed effectively by 15 min irradiation of NIR light at a dose of 40 μg mL−1. The effective bactericidal activity is ascribed to the high upconversion luminescence efficiency of β-NaYF4:Yb,Er,Gd and the layered two-dimensional nanosheet structure of 1T/2H-MoS2. Under 980 nm light irradiation, β-NaYF4:Yb,Er,Gd emits visible light, which is absorbed by MoS2, producing strongly oxidative holes and reductive electrons. Photogenerated electron–hole pairs were able to react with H2O, O2 and OH− to produce reactive species in aqueous solution. These reactive species are strong nonselective oxidizing agents for sterilization.