Characterizations and photocatalytic activity of nanocrystalline La1.5Ln0.5Ti2O7 (Ln = Pr, Gd, Er) solid solutions prepared via a polymeric complex method

Nanocrystalline La_1.5Ln_0.5Ti₂O₇ (Ln = Pr, Gd, Er) solid solutions were prepared by a polymeric complex method. The samples were characterized by X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (DRS), energy dispersive X-ray spectrum (EDS), thermogravimetric analyses (TGA) and differential thermal analyses (DTA). The photocatalytic activity of La_1.5Ln_0.5Ti₂O₇ (Ln = Pr, Gd, Er) was evaluated by the photocatalytic degradation of methyl orange (MO). La_1.5Gd_0.5Ti₂O₇ showed the best photocatalytic activity and it was supposed that the half-filled electronic configuration of Gd³⁺ can promote charge transfer and enhance the photocatalytic activity. The difference in the photocatalytic activity observed for La_1.5Ln_0.5Ti₂O₇ (Ln = La, Pr, Gd, Er) can be related to the different Ln 4f shell.