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

Abstract

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.