Synergistic plasmonic and upconversion effect enhanced the photocatalytic activity of the lanthanide-doped CaF2@TiO2-Au for antibacterial applications

The development of high-performance near-infrared (NIR) photocatalysts with long-term stability broaden the range of light absorption and improve the utilization rate of solar energy have not been explored sufficiently. Herein, a novel hybrid material of upconversion nanoparticle (NPs) CaF 2 : Yb, Er, Tm decorated with TiO 2 and Au NPs has been synthesized by a simple and robust solvothermal route for NIR light active photocatalysis. It has been found that effective energy transfer occurred from CaF 2 : Yb, Er, Tm to TiO 2 and Au NPs by a nonradiative luminescence resonance energy transfer process. The enhanced activity is attributed to the nanostructured architecture that favors the efficient charge transfer and the localized surface plasmon resonance effects of Au NPs. Thus, the heterojunction showed the synergetic effects of both upconversion and localized surface plasmon resonance features, which could broaden the absorption spectrum to the NIR. Our work demonstrates that CaF 2 :Yb,Er,Tm@TiO 2 -Au could be potential candidates for NIR active photocatalysts for environmental applications.