Preparation of a novel nanocomposite NaLuF4:Gd,Yb,Tm@SiO2@Ag@TiO2 with high photocatalytic activity driven by simulated solar light

Abstract

A novel nanocomposite photocatalyst NaLuF₄:Gd,Yb,Tm@SiO₂@Ag@TiO₂ was developed for the first time. This composite material has a sandwich structure, including a NaLuF₄:Gd,Yb,Tm upconversion nanocrystals (UCNCs) core, a media shell of amorphous SiO₂ decorated with Ag nanoparticles, and an outer shell of anatase TiO₂. The designed new structure takes advantage of the synergetic effect of UCNCs, Ag nanoparticles and TiO₂. The UCNCs absorb near-infrared (NIR) light and transfer energy to TiO₂, which extends the light responsive range of TiO₂ to the NIR region. Ag nanoparticles not only enhance upconversion luminescence of the UCNCs but also enhance light harvesting and improve charge separation of TiO₂. The results of photocatalytic applications show that the as-prepared catalyst has high photocatalytic activity. This study provides new insights into the fabrication of TiO₂-based nanocomposite photocatalysts with high catalytic efficiency through effective integration of upconversion material, noble metal and TiO₂ into a hetero-composite nanostructure.