The effect of lanthanide on the degradation of RB in nanocrystalline Ln/TiO2 aqueous solution

A series of Nd3+, Pr3+, Er3+, and Dy3+ (0.25-5 at.%) homogeneously doped nanocrystalline titanium dioxides (Ln/TiO2) were prepared by an easy sol-gel technique, and the roles of lanthanide doping on the photocatalytic activity in the degradation of rhodamine B (RB) in aqueous solution were studied. Both the concentration of the lanthanide dopant and calcination temperature showed significant effect to the photodegradation of RB. The photocatalytic activity of pure titania was drastically decreased when calcination temperature was at 700 °C, while the high photocatalytic activity was still maintained for lanthanide-doped samples. HPLC-MS method was used to study the degradation process, and it is demonstrated that the degradation of RB catalyzed by Ln/TiO2 was principally go through with a stepwise de-ethylation photochemical process.