Photocatalytic activities of LaFe_1−xZn_xO₃ nanocrystals prepared by sol–gel auto-combustion method

Nanophotocatalysts LaFe_1−xZn_xO₃ (x = 0, 0.05, 0.1, 0.3, 0.5) were successfully prepared by sol–gel auto-combustion method. The samples were characterized by X-ray diffraction (XRD), ultraviolet/visible absorption spectra (UV–vis), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The photocatalytic activities of the prepared samples were investigated for the photodegradation of methylene blue (MB). The results show that the lattice constant of LaFe_1−xZn_xO₃ nanocrystals increases due to the substitution of Zn for Fe, which leads to the lattice distortion. The absorption edges of Zn-doped LaFeO₃ display a red shift with a significant absorption between 400 and 500 nm. Doping with the Zn ions enhances the photodegradation rate of LaFeO₃ for MB. The LaFe_0.7Zn_0.3O₃ particles are spherical with mean grain size of about 20–30 nm, which exhibits the highest degradation rate of 75% under irradiation time of 150 min.