Abstract:

Europium (one of the rare earth element) was doped into Bi₂O₃ to extend the light response scope of bismuth oxide photocatalyst and
 the effects of europiumtobismuth ratio, concentration of ionic liquid, calcination temperature, calcination time and dosage of the catalyst on the photocatalytic activity of europium doped bismuth oxide were investigated. Methyl orange was used as the target pollutant. The optimum preparation conditions are europiumtobismuth ratio (n(Eu)∶n(Bi)) is 025, concentration of ionic liquid is 0.002 5 mol/L, calcination temperature is 400 ℃ and calcination time is 5 h. The optimum dosage of the catalyst is 5.0 g/L. Furthermore, the prepared sample under optimum conditions has well photocatalytic activity under visible light where the degradation rate of methyl orange is up to 92.57%. But the degradation rate of methy orange was only 29.26% when it was degraded by nondoped photocatalyst. The prepared samples were characterized by Xray diffraction (XRD) and ultravioletvisible diffuse reflectance spectroscopy (UVVis DRS) techniques. The results suggest that the prepared photocatalyst belongs to the tetragonal system. Based on UVVis spectra, the band gap of europium doped bismuth oxide is 2.37 eV which is 0.49 eV narrower than that of the nondoped photocatalyst. Absorption edge shows a red shift of 120 nm. Thus, europium doping extends the light response scope of bismuth oxide photocatalyst and provides a good photocatalytic activity.

Key words: photocatalyst, bismuth oxide, visible light, europium doping