Preparation Of Yb,N,F,B And Ga Co-doped Er³⁺:Y₃Al₅O₁₂ With TiO₂Composite Films And Studies On Visible-light Photocatalytic Activity

This study is primarily about the influence of doping some atoms (Yb, N, F, B,Ga) on the photocatalytic activity of up-conversion luminescence agent, Yb, N and Fco-doped Er3+:Y3Al5O12with TiO2composite films and Yb, B and Ga co-dopedEr3+:Y3Al5O12with TiO2composite films. From the results of the experiment, we canconclude that the doping of Yb can sensitize Er3+:Y3Al5O12, which contributes toincreasing the performance of up-conversion luminescence. And the doping of N andF with different electronegativities from O atom can enrich the molecular orbitalenergy levels of Er3+ion, which causes the absorption of wide band visible lightspectrum. And Al is replaced by B and Ga atoms, which B has smaller ionic diametercompared with Al and Ga has bigger ionic diameter compared with Al. The dopingsome atoms can change the symmetry of crystalline field around Er3+ion inEr3+:Y3Al5O12. It can be concluded that the host crystal in Er3+:Y3Al5O12may bechanged by doping of N, F, B and Ga. That is, Yb, N, F, B and Ga can decrease andenrich the difference of orbital energy levels, respectively. Meanwhile, it also reducesthe symmetry of crystal field around Er3+, which helps Er3+:Y3Al5O12absorb muchmore expansive range and larger amount of visible light. And then, when Yb, N, F, Band Ga co-doped Er3+:Y3Al5O12is put into TiO2for enhancing the photocatalyticperformance.In this study, several up-conversion luminescence agents were synthesized bysol-gel method. And then, the corresponding photocatalysts were prepared by sol-gelcoating process. The synthesized up-conversion luminescence agents and theircomposite films were characterized by X-ray diffraction (XRD), scanning electronmicroscope (SEM) and energy dispersive X-ray spectroscopy (EDX). And that, thephotocatalytic activities were detected through the degradation of Azo Fuchsine (AF)and Acid Red B (AR-B) dye in aqueous solution by UV-vis spectroscopy.Some key influence factors such as heat-treated temperature and heat-treatedtime on the photocatalytic activity of Yb, N and F co-doped Er3+:Y3Al5O12with TiO2 composite films and Yb, B and Ga co-doped Er3+:Y3Al5O12with TiO2compositefilms, as well as visible light irradiation time, other dyes, recycling used times andlayer number on the photocatalytic degradation were studied. At last, the experimentsalso indicated that the photocatalysts have a good photocatalytic activity to degradeother organic dyes under visible light irradiation.