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

The beta-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 beta-NaYF4:Yb3+,Tm3+@TiO2 core@shell photocatalyst consists of uniform hexagonal phase NaYF4 microcrystals rods and anatase TiO2 shells, and the beta-NaYF4:Yb3+,Tm3+@TiO2 exhibits strong near-infrared light absorption and the energy transfers from beta-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 980 nm laser. The results suggest that beta-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. (c) 2013 Elsevier B.V. All rights reserved.