Synthesis of Reduced Grapheme Oxide as A Platform for loading β-NaYF 4 :Ho 3+ @TiO 2 Based on An Advanced Visible Light-Driven Photocatalyst.

In this paper a novel visible light-driven ternary compound photocatalyst (β-NaYF4 :Ho3+ @TiO2 -rGO) was synthesized using a three-step approach. This photocatalyst was characterized using X-ray diffraction, Raman scattering spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Transmission electron microscopy, X-ray photoelectron spectroscopy, fluorescence spectrometries, ultraviolet-visible diffuse reflectance spectroscopy, Brunauer-Emmett-Teller surface area measurement, electron spin resonance, three-dimensional fluorescence spectroscopy, and photoelectrochemical properties. Such proposed photocatalyst can absorb 450 nm visible light while emit 290 nm ultraviolet light, so as to realize the visible light-driven photocatalysis of TiO2 . In addition, as this tenary compound photocatalyst enjoys effecitve capacity of charge separation, superior durability, and sound adsorb ability of RhB, it can lead to the red shift of wavelength of absorbed light. This novel tenary photocatalyst can reach decomposition rate of RhB as high as 92% after 10 h of irradiation by visible-light Xe lamp. Compared with the blank experiment, the efficiency was significantly improved. Recycle experiments showed that theβ-NaYF4 :Ho3+ @TiO2 -rGOcomposites still presented significant photocatalytic activity after four successive cycles. Finally, we investigated visible-light-responsive photocatalytic mechanism of the β-NaYF4 :Ho3+ @TiO2 -rGO composites. It is of great significance to design an effective solar light-driven photocatalysis in promoting environmental protection.