Advanced near-infrared-driven photocatalyst: Fabrication, characterization, and photocatalytic performance of β-NaYF₄: Yb³⁺,Tm³⁺@TiO₂ core@shell microcrystals

The β-NaYF₄:Yb³⁺,Tm³⁺@TiO₂ core@shell photocatalyst has been successfully fabricated by a simply hydrothermal method followed by hydrolysis of titanium isopropoxide (TTIP) with polyvinylpyrrolidone K-30 (PVP) as the coupling agent. The advanced near-infrared-driven photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, fluorescence spectrometer and UV-vis-NIR diffuse reflectance spectroscopy. It is found that β-NaYF₄:Yb³⁺,Tm³⁺@TiO₂ core@shell photocatalyst consists of uniform hexagonal phase NaYF₄ microcrystals rods and anatase TiO₂ shells, and the β-NaYF₄:Yb³⁺,Tm³⁺@TiO₂ exhibits strong near-infrared light absorption and the energy transfers from β-NaYF₄:Yb³⁺,Tm³⁺ to TiO₂ is confirmed. The photocatalytic activities of the catalysts were evaluated by the discoloration of Methylene Blue, Methyl Orange and Rhodamine B under the irradiation of 980nm laser. The results suggest that β-NaYF₄:Yb³⁺,Tm³⁺@TiO₂ core@shell composite is an advanced near-infrared-driven photocatalyst. Moreover the NIR-driven photocatalyst shows good stability for photocatalytic decoloration of dye in the recycled tests. This study suggests a promising system to utilize the NIR energy of sunlight for photochemical and photoelectrical applications based on TiO₂, which will contribute to the utilization of solar energy in the future.