https://doi.org/10.15255/KUI.2015.007
Published: Kem. Ind. 64 (7-8) (2015) 339−345
Paper reference number: KUI-07/2015
Paper type: Original scientific paper
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Synthesis, Characterization and Sonocatalytic Activity of Co/N/Er3+ : Y3Al5O12/TiO2 Films for the Degradation of Organic Dyes

L. Wang, J. L. Ren and C. S. Hao

Abstract

The sonocatalytic degradation of organic dyes (C.I. 50040, C.I. Reactive Red 1, C.I. Acid Orange 7) catalysed by Co/N/Er³⁺ : Y₃Al₅O₁₂/TiO₂ films was studied. For the preparation of Co/N/Er³⁺ : Y₃Al₅O₁₂/TiO₂ films, the sol-gel coating process was used. The phase composition, morphology, precursor at different temperatures and emitting light properties of the calcined powders were analysed by X-ray diffraction (XRD), absorption spectra and upconversion emission spectra. The X-ray diffraction of powder samples of Co/N/Er³⁺ : Y₃Al₅O₁₂/TiO₂ took on anatase mine peaks and upconversion luminous agent, respectively. Analysis of absorption spectra of amorphous Co/N/Er³⁺ : Y₃Al₅O₁₂/TiO₂ showed that doping N stretching vibration peak of water or hydroxyl adsorption, Co²⁺ ion had very strong absorption in 1.0–1.7 μm wavelength range, the transition luminescence of Er³⁺ ions was just on Co²⁺ ions absorption band. The emission spectrum indicated that Co/N/Er³⁺ : Y₃Al₅O₁₂/TiO₂ could launch green 500–560 nm and red 650–700 nm, 525, 550 and 660 nm peaks corresponding to ²H_11/2, ⁴S_3/2 → ⁴I_15/2 and ⁴H_9/2 → ⁴I_15/2 transition of Er³⁺. Doping Co and N enhanced the upconversion luminescence and absorption effect. Sonocatalytic degradation effect of organic dyes loading Co/N/Er³⁺ : Y₃Al₅O₁₂/TiO₂ was better when ultrasonic intensity was equal to 15 W cm⁻². The degradation ratios of aqueous solutions of these three kinds of organic dyes by ultrasonic irradiation were obviously lower than by ultrasonic irradiation together with Co/N/Er³⁺ : Y₃Al₅O₁₂/TiO₂ films in the same conditions. Degradation kinetics of organic dyes by ultrasonic irradiation and by ultrasonic irradiation cooperating with Co/N/Er³⁺ : Y₃Al₅O₁₂/TiO₂ films followed the first-order reaction.

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Keywords

Co/N/Er3+ : Y3Al5O12/TiO2, upconversion emission spectra, sonocatalytic, dye degradation